B&K 4070A User Manual

Model 4070A

User’s Manual

21.5MHz Multi Function Arbitrary Waveform Generator

B&K Precision

Model 4070A User’s Manual

PRODUCT AND DOCUMENTATION NOTICE: B+K Precision reserves the right to change this product and its documentation without prior notice.

Information furnished by B+K Precision is believed to be accurate and reliable. However, B+K Precision assumes no responsibility for its use, nor for any infringement of patents, or other rights of third parties, which may result from its use. No license is granted by implication or otherwise under the patent rights of B+K Precision.

PRINTED IN U.S.A.

Printing History Second Edition 12/2002

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

B+K Precision Corp. Tel: (714) 921-9095 Internet: http://www.bkprecision.com

28820 Savi Ranch Parkway Fax: (714) 921-6422 Yorba Linda, CA 92887-4604

Table of Contents

1.0 Introduction

1.1 Description ..................................................................................................................................................................2

1.2 Feature summary .........................................................................................................................................................3

2.0 Installation and setup

Detail explanation of input and output connectors .......................................................................................................4

3.0 Operating controls and keys

3.1 Mode key...................................................................................................................................................................8

3.2 Field arrow keys........................................................................................................................................................8

3.3 Store/Recall key........................................................................................................................................................8

3.4 Offset key...................................................................................................................................................................8

3.5 Trigger key.................................................................................................................................................................9

3.6 Numeric keys (0 to 9, -.).........................................................................................................................................9

3.7 é, ê, è, ç keys....................................................................................................................................................9

3.8 Clear key.....................................................................................................................................................................10

3.9 MHz/dBm, KHz/Vp-p/Sec, Hz/mVp-p/mS keys....................................................................................................10

3.10 One Touch Mode keys............................................................................................................................................10

4.0 Operating guide.

4.1 Changing frequency...................................................................................................................................................11

4.2 Changing level............................................................................................................................................................11

4.3 Changing operating modes.......................................................................................................................................11

4.4 Operating mode selections........................................................................................................................................11

4.5 Changing values.........................................................................................................................................................12

4.3.1 Modifying an existing value..................................................................................................................................12

4.3.2 Entering a new value...............................................................................................................................................12

5.0 Mode descriptions

5.1 Basic Sinewave (CW) mode.....................................................................................................................................13

5.2 Internal AM mode.....................................................................................................................................................14

5.3 External AM mode.....................................................................................................................................................15

5.4 Internal FM mode......................................................................................................................................................16

5.5 External FM mode......................................................................................................................................................17

5.6 Internal PM mode......................................................................................................................................................18

5.7 External PM mode......................................................................................................................................................19

5.8 Sweep mode...............................................................................................................................................................20

5.9 Internal FSK mode.....................................................................................................................................................22

5.10 External FSK mode....................................................................................................................................................23

5.11 Burst mode................................................................................................................................................................24

5.12 Internal SSB mode....................................................................................................................................................25

5.13 External SSB mode....................................................................................................................................................26

5.16 DTMF Generation mode..........................................................................................................................................27

5.17 DTMF Detection mode............................................................................................................................................29

5.18 Power & Voltage Measurement mode...................................................................................................................30

5.19 Arbitrary mode..........................................................................................................................................................31

5.20 Remote mode.............................................................................................................................................................31

5.21 Other mode................................................................................................................................................................31

5.22 Internal BPSK mode.................................................................................................................................................32

5.23 External BPSK mode.................................................................................................................................................33

5.24 Dual tone Generation mode....................................................................................................................................34

5.25 Data Modulation mode............................................................................................................................................36

5.26 Voltage Controlled Oscillator (VCO) mode...........................................................................................................39

6.0 Remote operation

6.1 Introduction..................................................................................................................................................................40

6.2 Hookup..........................................................................................................................................................................40

6.3 Checking your connection with Hyper Terminal....................................................................................................40

6.4 Operation......................................................................................................................................................................41

6.5 Programming Rules......................................................................................................................................................41

6.6 Remote control command List...................................................................................................................................42

6.7 Examples........................................................................................................................................................................45

7.0 Arbitrary waveform system

7.1 Arbitrary Waveform Quick Start Guide....................................................................................................................46

7.2 Introduction to the Arbitrary Waveform Generator

7.2.1 Description of the Arbitrary Waveform System..................................................................................................47

7.2.2 Feature Summary ......................................................................................................................................................48

7.3 Switching to the Arbitrary/Function/Pulse Generator Modes .............................................................................48

7.4 Arbitrary Waveform Mode........................................................................................................................................49

7.5 Function Generator Mode..........................................................................................................................................50

7.6 Pulse Generator Mode................................................................................................................................................51

7.7 Downloading Arbitrary Waveforms

7.7.1 Using WAVELOAD.EXE........................................................................................................................................52

7.7.2 Using your own program.........................................................................................................................................53

7.8 Arbitrary Waveform Data Formats

7.8.1 Floating Point Format...............................................................................................................................................54

7.8.2 Time & Value Floating Point Format (.CSV, .PRN)..............................................................................................55

7.8.3 Digital Format............................................................................................................................................................56

7.8.4 Integer Format...........................................................................................................................................................57

7.8.5 Hexadecimal Format..................................................................................................................................................58

7.8.6 Binary Format............................................................................................................................................................59

7.9 Multiple Units Locking

7.9.1 Introduction and Hookup........................................................................................................................................60

7.10 Example Arbitration Program ARB.BAS................................................................................................................62

8.0 DC Operation Option

8.1 Specifications and hookup.........................................................................................................................................69

9.0 Specifications .....................................................................................................................................................70

10.0 Software CD

10.1 Contents of the accompanying disk.......................................................................................................................71

Appendix A RS-232 remote control example host program .....................................................................................72

Appendix B Application example: Television remote control................................................................................77

Warranty information ......................................................................................................................................81

1.0 Introduction

Figure 1.0-1: The BK Precision model 4070A

This manual contains operating instructions for the BK Precision Model 4070A Signal Generation and Processing Engine. Complete specifications for the Model 4070A are given in Chapter 9.

BK Precision 4070A User Manual Rev.2.2

1.1 Description

Figure 1.1-1: 4070A front panel

The Model 4070A is a versatile signal source capable of generating a variety of waveforms, including CW and wideband sweeps from D.C. to 21.5 MHz in steps of .01 Hz. The signals are generated using direct digital waveform synthesis (DDS) techniques for high accuracy and precision. AM, FM, PM, and FSK modulation types are available. A high speed Digital Signal Processor (DSP) controls every aspect of the DDS system and is used internally for the precise generation and processing of all modulating waveforms. DSP technology in 4070A allowed implementing additional modes to analyzes an externally applied signal such as DTMF detection and power level measurement. The 4070A is designed to supply an output signal level of 20.0 Vp-p with an offset voltage of +/- 6.0V. The output impedance is 50O; therefore the 50O loaded output level is 10.0 Vp-p, with an offset voltage capability of +/- 6.0V. The output level and offset voltages can be adjusted with a resolution of 1 mV. Output levels can also be specified in dBm with 0.1dBm resolution. The front panel, shown in figure 1.1-1, has two output connectors. The SIG Out connector is the main signal output. The SYNC Out connector is a TTL/CMOS compatible square wave output. It is a "hard limited" version of the main output and is available in al l modes. The SYNC Output is signal +5V and is useful for driving digital circuitry. The front panel of the Model 4070A includes a full numeric keypad and rotary knob to allow quick adjustment of any numeric value and gives the user the ability to manually adjust a value across a wide range. The LCD display is a large 2 line by 40-column display with backlight. It is large enough to display all operating parameters simultaneously and thus eliminate tedious submenus. The user can select a modulating waveform that is either internally generated or externally supplied. External signals in the DC to 35 KHz range could be used for 4070A external modulation. External modulation connector is located on the back of the unit. This input is high impedance (about 30KO) to avoid loading the source of the signal. The unit also features an external digital input, located on the back of the unit, which serves several purposes depending on the mode. For most modes, it serves as a gate to switch the RF output signal on and off. In external FSK or BPSK mode, it is a high-speed data input for FSK or BPSK digital modulation of the output waveform at rates up to 3 MHz. In modes that have a trigger function (Burst, Triggered Sweep, etc.) this input ser ves as an external trigger which triggers a sweep or burst on the rising edge of the input. The unit also features an RS232 connector on the back panel of the unit. This permits the user to remotely control the 4070A using ASCII characters. No special hardware or protocols are needed; any dumb terminal or computer serial port can be used. On-line help menu that lists all remote control commands to the terminal is available. The baud rate is adjustable up to 115.2 Kbps. Software upgrades are also dow nloaded to internal Flash memory using this port. An Arbitrary Waveform Generator lets the user design custom waveforms on a PC and downloads them to the 4070A for generation. Up to 32,768 unique points may be specified and generated by a 12 bit DAC with a sampling adjustable from 0 Hz to 40 MHz in .01 Hz steps. A logic waveform may also be generated simultaneously with the analog waveform. The unit will accept many popular data formats for maximum flexibility. Arbitrary Waveforms may be conveniently saved to nonvolatile memory.

BK Precision 4070A User Manual Rev.2.2

Included with the Arbitrary Waveform Generator is a full featured Function Generator and Pulse Generator. The function generator offers a set of pre-stored waveforms, which are generated using the Arbitrary Waveform system. The Pulse Generator allows the user to generate pulse waveforms with varying amplitude, offset, frequency and duty cycle.

1.2 Feature summary

• Each unit is individually calibrated to ensure accurate output frequency, level, and offset voltage.

• Output level: 4mVp -p to 20Vp -p (unloaded). Output level can be entered with 1 mV or .1 dBm resolution.

• Output offset: 0 mV to +/- 6.0 V. Output offset can be entered with 1 mV resolution.

• TTL/CMOS compatible logic output drives digital circuits directly.

• Flash Memory is used for code storage to enable easy software updates.

• 10 complete instrument setups can be individually stored or recalled.

• Unit has a large, easy-to-read illuminated LCD display, which shows all operating parameters for each setup. No

confusing submenus.

• Full numeric keypad and rotary encoder make entering and adjusting parameter values easy.

• Standard RS232 port included. Remote control operation requires no special hardware or software. Baud rate is

programmable. All commands use ASCII characters. Programming examples ar e included.

• External modulation input is wideband: DC to 35 KHz. High input impedance (30K O avoids loading the source

signal.

• External logic input allows user to gate output signal on/off under logic control. It can also be used as an external

trigger signal.

External FSK and BPSK data is also brought in on this connector.

Modes

• Basic Sinewave • DTMF Generation

• Internal/External AM • DTMF Detection

• Internal/External FM • Voltage & Power Measurement

• Internal/External PM • Burst (Continuous or Int/Ext trig)

• Internal/External SSB • Sweep

• Internal/External BPSK (Linear/Log/Continuous/Triggered/Up/Down)

• Internal/External FSK • Dualtone Generation

• Data Modulation • Voltage Controlled Oscillator (VCO)

Options (contact factory for availability):

• High stability time-base

• DC Operation

BK Precision 4070A User Manual Rev.2.2

2.0 Installation and setup.

This section discusses how to properly connect the 4070A to your equipment. The following diagrams identify the connectors and show typical hookups.

Figure 2.0-1: Front Panel Connectors

1. SYNC out connector

This connector provides a TTL/CMOS signal, +5V logic level useful for driving digital circuitry. This output is capable of driving TTL or CMOS loads with current capability +/- 24 mA.

In all sinewave and modulation modes except sweep, this connector supplies squarewave ver sion of the signal on the SIG Out connector. It has a fixed 50% duty cycle.

In the Sweep mode, this connector provides a high going pulse at the beginning of each sweep. In the Arbitrary Waveform Generator mode, the user may set this output high or low on any data point(s) in the

Arbitrary Waveform. This feature could be used to create a pattern of logic pulses or a triggering or synchronizing signal, which accompanies an analog waveform.

In the Function Generator mode, a high going pulse is given on this output at the start of each function waveform. This useful feature allows the user to synchronize the functions to other events.

In the Pulse Generator mode, this output follows the SIG Out signal. The signal on this output has the same frequency and duty cycle as signal on the SIG out connector. However the signal on this connector is not variable in amplitude and offset; it set to +5V, to provide a convenient interface with TTL/CMOS digital logic.

2. SIG Out connector

This is the main signal output. It has a source impedance of 50?, and can supply signals as large as 20 Vp-p into an open circuit or 10Vp-p into a 50O load. It can also supply a DC offset voltage of +/- 6.0V into a 50O load.

*** Caution ***

Although the output is protected against short circuits, you should NEVER connect SIG Out to a voltage

or signal source. This may overload the output and damage the 4070A .

BK Precision 4070A User Manual Rev.2.2

3. External Modulation In connector

The External Modulation In connector, located on the rear of the 4070A, accepts an external analog signal as illustrated here:

Figure 2.0-3: Connecting an external signal

On this connector, the user supplies a base band signal (below 50 KHz) that is used to modulate an output carrier. (microphone is shown here as an example). It also serves as the input connector for DTMF signals in DTMF Detection mode, and signals to be measured in the Power Level and Voltage Measurement mode.

This input is high impedance (about 30KO). It was made high impedance to avoid loading down the circuit supplying the signal.

This input is DC coupled within the 4070A. The signal on this input is internally low pass filtered to a cutoff frequency of 50KHz.

The input level for this connector is ±5V max. For external modulation modes, a 1V p-p signal will fully modulate the carrier. If you apply a higher -level signal than 1 Vp-p, the input signal will be distorted. The distortion that will take place under these conditions is a "hard limiting" type (i.e. the wavefor m will "flat top" at the positive and negative extremes). Under these conditions, the word "Overld" will be printed to the LCD for input levels that are too high.

*** Caution ***

External signals greater then ±25Vp-p range on external applied to modulation input may damage the 4070A.

BK Precision 4070A User Manual Rev.2.2

4. External Trigger/Gating/FSK/BPSK input

The External Trigger/Gating/FSK/BPSK In connector accepts an external digital signal on the rear of the unit as illustrated here:

Figure 2.0-4: Driving the Ext Trigger/Gating/FSK/BPSK input

On this connector the user supplies a digital signal, which serves a variety of purposes, depending on the operating mode of the 4070A.

This input is a high impedance input (about 80KO) and can safely accept input levels from -10V to +10V. The input uses a comparator with a switching point of about 1.4V permitting either TTL or CMOS logic to drive this input. The input has hysterics, too, so you can apply analog signals to this input (i.e. a sinewave).

This input has an internal pull down resistor which holds it in the low or "0" state when left open. In most modes, this input can be used to switch the output signal on or off. When driven high, the output signal is

gated off. This function can be perform ed up to 3 MHz. When the output is gated off, the DC level on the Sig Out jack is unpredictable. The Gating input "freezes" the output waveform at the output voltage is held to the voltage value that existed at the moment the Gating input went high. When the Gating input is brought low again, the output waveform resumes from the same point.

In the External FSK and BPSK modes, this input is used to bring in digital data for FSK or BPSK modulation. In the Burst and Triggered Sweep modes, this input is used as a trigger signal. External High logic signal will

triggers a sinewave burst or starts a sweep. In the Continuous Sweep mode, driving this input high can halt the sweep. The sweep will resume when this input

is brought low again. In the Arbitrary, Function, and Pulse Generator modes, this input serves as a trigger signal input. If Triggered

mode is selected, the generation of your arbitrary/function/pulse waveform will commence on the rising edge of the trigger signal.

*** Caution ***

Be careful to ensure that the input signal does not exceed the +/- 10V limit. Permanent damage to this input may

result by exceeding this input voltage limit.

BK Precision 4070A User Manual Rev.2.2

Figure 2.0-5: Rear panel connectors

5. External Reference Input / Ext Arb. Clock connector

This connector accepts an external sample clock for the Arbitrary Waveform Generator when the unit is in External Clock or Lock Slave modes. The signal level on this input must be between 0V and +5V and is intended to be driven by TTL/C MOS logic. (For more information on Arb Locking, refer to the chapter “Multiple Unit Locking.”) This connector is also reserved for the addition of an external time base reference option.

*** Caution ***

Logic signals outside the 0V to +5V range on this input may damage the 4070A.

6. External Arb Sync In / Out connector

This connector accepts an external synchronizing signal when the unit is in Lock Slave mode. (For more information on Arb Locking, refer to the chapter “Multiple Unit Locking.”) The signal level on this input must be between 0V and +5V, TTL/CMOS.

*** Caution ***

Logic signals outside the 0V to +5V range on this input may damage the 4070A.

7. RS232 Interface connector

This port is used for: remote operation of the 4070A, software upgr ades to internal Flash memory. To use the remote control feature, attach the serial port on a computer or terminal to the RS-232 Interface connector, on the back panel of the 4070A, on PC to the serial port connector. The wiring is different for each type of connector. For cabling diagrams, see chapter 6 "Remote Operation." Baud rate is factory-set to 9600 but may be changed via the front panel or RS232 port. The other serial port parameters are 1 start bit, 8 data bits, 1 stop bit, and no parity. An ASCII "hello" screen is printed to the terminal on power-up. For further information, refer to chapter 6.

8. Line in connector

A standard IEC power cord inserts directly into the back of the 4070A. The input is auto-ranging and may be 100240VAC, 47-63 Hz.

BK Precision 4070A User Manual Rev.2.2

3.0 Operating controls and keys.

3.1 Mode key

The Mode key is used to change the operating mode of the 4070A. When pressed, the LCD display is cleared and the question Mode? is displayed. The Mode key acts as a shift type key in that the meaning of each button on the front panel changes to that described by the red wording beneath it. To enter Sweep mode, for example, first press the Mode key and then press the number 4 key. You can exit the Mode screen by pressing the red Mode key again. The display returns to the previous mode unchanged. Some modes are available on the 4070A that are not printed on the front panel. To access these modes, press the Mode key, and then the Clear key to bring up a scroll menu from which you can select one of these extra modes.

3.2 Field arrow keys

Field arrow keys are used to move the cursor to the numeric entry field that you wish to edit. Each time the key is pressed, the cursor is advanced to the next field on the display. A flashing character indicates the cursor position. When the cursor is advanced to a new field, it is placed at the last -used position within that field. You then use the è or ç keys to move the cursor side-to-side within the field. One of the valid cursor fields is "off". When the cursor is off, (i.e. there are no flashing characters anywhere) then all numeric values are frozen and cannot be changed until the cursor is switched back on. This feature is designed as a "lockout" function to safeguard parameter values from being changed by inadvertent key presses or turns of the rotary knob.

3.3 Recall / Store key

Recall/Store key is used to store or recall an instrument setup to or from 10 storage locations in non-volatile memory. By using the Store/Recall function, you can save all operating parameters so they can be quickly recalled even though the unit had been turned off. The offset voltage and currently selected RS232 baud rate are also saved.

If the instrument setup is saved while the unit is in Arbitrary Waveform mode, the currently loaded arbitrary waveform is stored to nonvolatile memory. Although mode parameters such as Clock Frequency, Level, etc. can be saved to 10 locations, the arbitrary waveform is always saved to/recalled from a single location. The entire waveform array of up to 32,768 points is saved.

To recall an instrument setup, press the Store/Recall key once. The LCD display will be cleared and the question: Recall (0-9)? Will appear, asking you to press a numeric key 0 to 9 to select one of ten available locations to use. You can abort this question without saving a configuration by pressing any key other than 0 to 9. If you then press the 5 keys, for example, the display will show Configuration recalled from location 5 to confirm the recall operation.

To save an instrument setup, press the Store/Recall button twice. The LCD display will be cleared and the line Store (0-9)? will appear, asking you to select one of ten available locations to store the configuration. You can abort the question without recalling a configuration by pressing any key other than 0 to 9.

NOTE: Location 0 is special. The instrument state stored to location 0 will be recalled on power -up. This includes the serial port baud rate.

3.4 Offset key

The Offset key is used to specify a DC offset voltage to be added to the output signal. When this key is pressed, the LCD display is cleared and the cursor is placed in a numeric field to enter the offset voltage. Both positive and negative voltages can be entered. To exit the offset entry screen and return to the current mode, press the Offset key again. The offset voltage value can be entered in the same manner as any other numeric value. You can also use the wheel to modify a particular digit in the value. Any voltage within the range of -6.0 to +6.0 can be entered.

NOTE: The offset voltage specified is a 50O load value. This is the voltage that will appear across a 50O load connected to the SIG Out connector. If you are connecting the output to a high impedance load, the output voltage will be twice that entered.

BK Precision 4070A User Manual Rev.2.2

NOTE: Care must be taken when specifying an output offset voltage and level such that the output does not clip. The loaded output cannot swing higher than +6.0V or lower than -6.0V. Therefore:

¦Offset voltage¦ + 1/2 * Vp-p < 6.0

The 4070A can be used as a variable voltage source by setting the output frequency to 0.0 Hz while in Sinewave mode. Then set the offset voltage to the desired output voltage. Remember, the output impedance is 50 ohms. Up to +/- 70 mA can be drawn from the output under these conditions.

This key is also used to select the RS-232 baud rate after the Mode key is pressed once. By pressing Mode then Offset, a menu of baud rates for the 4070A is presented. For more information, refer to the chapter on Remote Mode.

3.5 Trigger key

The Trigger key is used in modes that require a trigger event to begin a process. Triggered Sweep mode uses this key to begin a sweep. Triggered Burst and Data Modulation modes also use this key to begin the generation of a burst signal s. Arbitrary Waveform, Function Generator and Pulse Generator modes use this key to begin the generation of a waveform in Triggered mode.

In modes that require a trigger, the trigger can come from three sources:

1. Pressing the Trigger key

2. Applying a low -to-high transition on the Ext Trigger In connector

3. Sending an ASCII "T" to the RS-232 port The 4070A will simultaneously accept a trigger from all of the above sources.

3.6 Numeric keys (0 to 9, - and.)

The 0 to 9, - and . keys are used to enter a numeric value. The - key is only accepted when entering numeric

values that can be negative, i.e. dBm or offset values. The key press is ignored otherwise.

In DTMF generation mode, the. key is used to generate the star ("*") DTMF digit and the - key is used to

generate the pound ("#") DTMF digit. These keys are also used to select a mode after the Mode key is pressed once. These keys are then used to select a

mode indicated by the blue text written beneath these keys.

3.7 é, ê, è, ç keys

The arrow keys are used to move the cursor and edit numeric values. The è and ç keys move the cursor side to side within a cursor field. They can be used to position the cursor

over a digit within the field to modify. Once the cursor is over the desired digit, use the é or ê key to increment or decrement that digit.

Pressing the é key increments the digit under the cursor and has the same effect as rotating the knob clockwise 1 tick. Pressing the ê key decrements the digit under the cursor and has the same effect as rotating the knob counter clockwise 1 tick.

While a numeric value is being typed in, you can use the ç key as an erase key. Pressing this key erases the last digit entered, allowing you to correct typing mistakes.

All arrow keys have an "auto repeat" feature. By holding down the key, the key will repeat continuously until released. This makes it more convenient to quickly sweep a value or move the cursor within a field.

These keys are also used to select a new operating mode after the Mode key is pressed. The arrow keys are then used to select the mode indicated by the blue text beneath the key.

In DTMF Generation mode, these keys specify DTMF digits A, B, C, D which are signaling tones used in the telephone network but not found on a typical telephone. For more information, refer to the chapter on DTMF Generation mode.

BK Precision 4070A User Manual Rev.2.2

3.8 Clear key

While the cursor is within a numeric field, the Clear key erases all digits within the field, allowing the user to start over when entering a value.

This key is also used to select the "Other" mode after the Mode key is pressed once. By selecting Other Mode, a menu of extended modes for the 4070A is presented. See the chapter on Changing Modes.

3.9 MHz/dBm, KHz/Vp-p/Sec, Hz/mVp-p/mS keys

These keys are used to select the units for a numeric value once it has been typed into a parameter field. After entering all digits for a value, you must press one of these keys to complete the entry of the value. In other words, these keys serve as an "enter" key since a value being edited in a cursor field is not accepted and processed until one of these keys is pressed.

After pressing one of these keys, the 4070A will make a double clicking noise to indicate that the value has been accepted. If the entered value is outside the allowable range for the field, the 4070A will give an error beep and set the value to its upper or lower limit.

To enter a value in Volts or milli volts, use the Vp -p and mVp-p keys, respectively. When entering a value that has units not listed on the key (i.e. percentage, ohms, etc.), any one of these three keys

will work as an enter key.

3.10 One Touch Mode Keys

These keys immediately switch the function generator to the operating mode indicated on the key. These keys make it more convenient to switch to frequently-used operating modes

BK Precision 4070A User Manual Rev.2.2

4.0 Operating guide

Turn 4070A on. After a display of the hardware and software versions and serial number, the unit enters the Basic Sinewave mode of operation. The 4070A defaults to generating a 1.0 MHz sinewave at a level of +10.0 dBm.

4.1 Changing frequency

To change the frequency, press the Right Field Arrow button once. The cursor will move to the frequency field. A flashing digit indicates the cursor position.

You can change the frequency two different ways. You can enter a new value or you can modify the current value.

To enter a new value, type in the frequency using the numeric keypad. Then press the MHz key for MHz, or the KHz key for KHz, or the Hz key for Hz. The unit will make a two beeps sound to indicate that a new frequency value has been accepted.

To modify an existing value, use the è and ç keys to position the cursor over the digit you wish to change. Then press the é or ê key to increment or decrement that digit. Alternatively, you can turn the rotary knob clockwise or counterclockwise to adjust the digit's value.

4.2 Changing level

To set a new output level, press the Right Field Arrow button until the cursor flashes on the right hand side where the level is displayed. You can change the level two ways. You can type in a new value or adjust it with the wheel or arrow keys. To enter a new level, type in the new level value using the numeric keypad. For a negative dBm value, press the - key while entering the value. Finally, press the dBm key to enter the value as dBm or the Vp-p or mVp -p keys to enter the new value as a peak-to-peak voltage.

NOTE: The level you're entering here is considered a loaded level, i.e. the level that will appear across a 50O load connected to the output.

To modify an existing level value, use the è and ç keys to position the cursor within a field. Place the cursor over the digit you wish to change and press the é or ê key to increment or decrement the digit. Alternatively, you can turn the rotary knob clockwise or counterclockwise to adjust the digit's value.

4.3 Changing operating modes

To select another operating mode, press the red Mode key once. When pressed, the LCD display is cleared and the question Mode? is displayed. The Mode key acts as a shift type key in that the meaning of each button on the front panel changes to that described by the blue wording beneath it. To enter the SWEEP mode, for example, first press the Mode key and then press the number 4 key.

You can then use the Field Arrow keys to move the cursor to the parameter you wish to change. Each numeric value can be entered or modified in the same manner described above. This manual contains a separate chapter for each mode, which describes in detail all parameters on the LCD display. User could switch to other generating modes by pressing One Touch Mode Selection key or “Mode” key for more options.

4.4 Operating mode selection.

If you wish to select a new operating m ode for the 4070A, press the red Mode key once. When pressed, the LCD display is cleared and the question Mode? is displayed. The Mode key acts as a shift type key in that the meaning of each button on the front panel changes to that described by the red wording beneath it. To enter Sweep mode, for

example, first press the Mode key and then press the number 4 key. You can exit this question either by pressing the blue Mode key again or by pressing any key that does not have red text beneath it. The 4070A will then return to the current mode unchanged.

Some modes are available on the 4070A that are not printed on the front panel. To access these modes, press the Mode key, and then the key labeled "Other" (Clear key) to bring up a scroll menu, which displays the additional modes. You can scroll through the list with the arrow keys or the wheel. To select one of these modes, enter its menu number. User could switch to other generating modes by pressing One Touch Mode Selection key or “Mode” key for m ore options.

BK Precision 4070A User Manual Rev.2.2

4.5 Changing values

For each operating mode, the LCD display shows a number of fields that hold operating parameters for the selected mode (i.e. sweep start frequency, stop frequency, etc.). To change the value of a parameter, you m ust first move the cursor to the desired field on the display. To do this, press one of the Field Arrow keys until the cursor appears in the desired field. When the cursor is advanced to a new field, it is placed in the rightmost position within that field and is indicated by a flashing character. One of the valid cursor fields is "off". When the cursor is off, numeric values cannot be altered until the cursor is switched back on. This feature is designed as a "lockout" function to safeguard parameter values from being changed by inadvertent key presses or turns of the rotary knob. Once the cursor has been moved to the desired field, the field value can be changed in two ways. You can modify a current value or you can enter a new value.

4.5.1 Modifying an existing value

To modify an existing value, first move the cursor to the desired field using the Field Arrow keys. Then use the è and ç keys to position the cursor over the digit you wish to change. Press the é or ê key to increment or decrement that digit. Alternatively, you can turn the rotary knob clockwise or counterclockwise to adjust the digit's value. Attempting to set a parameter to a value outside the allowable range will cause the 4070A to beep and set the parameter to its maximum or minimum permissible value.

Non-numeric values toggle between preset values. (An example is Linear or Log type sweep). You can toggle

these values by pressing an arrow key or turning the wheel. You can also press the 0 key to select the first value or the 1 key to select the second value.

4.5.2 Entering a new value

To enter a new value, first move the cursor to the desired field using the Field Arrow keys. Use the keyboard to type in new value. If you make a mistake while typing in a value, use the following three keys to correct mistakes:

Use ç as a "backspace" key to erase the last digit you typed. Use clear to erase all characters from the field value and start over. Use a Field Arrow keys to abandon the editing process, restore the old value, and move the cursor to the next

field.

Once all numbers are entered, select which units apply to the newly entered digits:

To enter a frequency, use the MHz, KHz, or Hz keys. To enter a peak -to-peak voltage, use the Vp-p or mVp-p keys. To enter a dBm value, use the dBm key. To enter a value in Volts, use the Vp -p or mVp-p keys. (Ignore the p-p designation). To enter a time value, use the Sec or mS keys.

Some units have dimensions not listed on these three keys. AM mode has a value in percentage, for example. In this case, any of the three units keys will work. To type in a new percentage value, for example, type the percentage digits and then press the MHz/dBm key or the KHz/Vp-p/Sec key or the Hz/mVp-p/mS key (all are equivalent).

The 4070A will confirm that a new value has been successfully entered by double beep. If a value is entered that

is outside the allowable range, the 4070A will beep and set the parameter to its maximum or minimum permissible

value. An easy way to determine a maximum allowed value is to enter a very large value (i.e. 999 MHz or Volts,

etc.) and observe the value that the 4070A returns.

BK Precision 4070A User Manual Rev.2.2

Sinewave Mode

5.0 Mode descriptions

The following pages describe each operating mode of the 4070A. The meaning of each parameter that appears on the LCD display is described in detail.

5.1 Basic Sinewave (CW) Mode

Introduction

The Basic Sinewave (CW) mode generates a sinewave of fixed frequency and level. This mode could be entered by pressing the Sinewawe One touch mode selection key

NOTE: In this mode you can set the output frequency to 0 Hz and, by specifying an offset voltage, use the 4070A as a variable voltage source (with a 50O output impedance). Up to +/- 70 mA can be drawn from the SIG Out output.

Sinewave Mode Parameters

The Sinewave mode has the following front panel display:

1 2

1,000,000.00 Hz -10.0 dBm

Figure 5.1-1: Sinewave mode display

1. Frequency

In this field enter the frequency of the sinusoid, from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

2. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in

0.1 dBm steps. NOTE: The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O

load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.

Offset

By pressing this key, you can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage on this jack (+3V to +10V) will turn off the output signal. A logic low voltage on this jack (0V to -10V) will leave the output signal on. For further information on the Ext Gating Input, refer to section 2.0.

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Int AM: 1,000 Hz

Percent Mod: 100%

134

5.2 Internal AM Mode

Introduction

The Internal AM mode generates an amplitude-modulated signal form with fixed carrier and modulating frequencies. An internally generated sinusoid is used as a modulating signal to vary the amplitude of a carrier sinusoid. The modulation waveform is not suppressed carrier; i.e. a fixed amount of carrier power is always present in the modulated signal. . Internal AM mode could be entered by pressing “Mode”> “AM” >”1” key at any time.

Internal AM Mode Parameters

The Internal AM mode has the following front panel display:

1,000,000.00 Hz PEP level: -10.0 dBm

Figure 5.2-1: Internal AM mode display

1. Modulating Frequency

In this field enter the frequency of the modulating sinusoid, from 0 Hz to 10,000 Hz in 1 Hz steps.

2. Percentage modulation

In this field enter the degree to which the modulating signal is allowed to change the carrier amplitude. You may

enter from 0% (no change) to 100% (maximum change) in 1% steps. To enter a value, type 1 to 3 numeric digits. If you type 3 digits, the value is automatically entered. If you only type 1 or 2 digits, you can press the MHz key or the KHz key or the Hz key (all are equivalent) to enter the percentage value.

3. Carrier Frequency

In this field enter the frequency of the carrier, from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

4. PEP Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1

dBm steps. NOTE: The level specified in Internal AM mode is the Peak Envelope Power, or PEP. As a peak -to-peak value,

this level represents the maximum peak -to-peak voltage swing that will result from a 100 percent modulated carrier. If no modulating signal were applied, the unmodulated carrier would have only half the peak -to-peak swing of a 100% modulated carrier.

NOTE: The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high level turns off the output. For further information on the Ext Gating Input, refer to section 2.0.

BK Precision 4070A User Manual Rev.2.2

External AM

Input gain: .999

132

5.3 External AM Mode

Introduction

External AM mode generates amplitude-modulated signal of fixed carrier frequency, were externally supplied signal is used as a modulating signal to vary signal modulated frequency and depth. Modulated frequency, output level, input gain and DC offset values could be manually entered from the front panel keypad in this mode. External signal gating options is available in this mode. External AM mode could be entered by pressing “Mode”> “AM” >”2” key at any time.

External AM Mode Parameters

The External AM mode has the following front panel display:

1,000,000.00 Hz PEP level: -10.0 dBm

Figure 5.3-1: External AM mode display

1. Input Gain

In this field specify a value used to scale the input signal. With a value of .999, a 1 Vp-p signal on the input will result in 100% modulation of the carrier amplitude. You may enter a value from 0 to .999. (The gain value is always less than 1.0). To enter a value, type 1 to 3 numeric digits. If you type 3 digits, the value is automatically entered. If you only type 1 or 2 digits, you can press the MHz key or the KHz key or the Hz key (all are equivalent) to enter the gain value.

2. Carrier Frequency

In this field enter the frequency of the carrier, from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

3. PEP Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1mV steps or from -44.0 dBm to +24.0 dBm in 0.1 dBm steps.

NOTE: The level specified in External AM mode is the Peak Envelope Power, or PEP. As a peak -to-peak value, this level represents the maximum peak -to-peak voltage swing that will result from a 100 percent modulated carrier. If no modulating signal were applied, the unmodulated carrier would have only half the peak -to-peak swing of a 100% modulated carrier.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage turns off the output. For further information on the Ext Gating Input, refer to section 2.0.

BK Precision 4070A User Manual Rev.2.2

Int FM: 1,000 Hz

Pk dev: 10,000 Hz

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5.4 Internal FM Mode

Introduction

Internal FM mode generates frequency-modulated signal of fixed amplitude. It used internally generated signal to modulate frequency of carrier signal. Modulated and modulating frequency, output level, deviation, and DC offset values could be manually entered from the front panel keypad in this mode. External signal gating options is available in this mode. Internal FM mode could be entered by pressing “Mode”> “FM” >”1” key at any time.

Internal FM Mode Parameters

The Internal FM mode has the following front panel display:

1,000,000.00 Hz -10.0 dBm

Figure 5.4-1: Internal FM mode display

1. Modulating Frequency

In this field enter the frequency of the modulating sinusoid. You may enter from 0 Hz to 10,000 Hz in 1 Hz steps.

2. Peak Frequency Deviation

In this field specify the degree to which the modulating signal is allowed to change the carrier frequency. You may enter from 0 Hz (no change) to 5.0 MHz in 1 Hz steps This parameter is a peak value. If the deviation were 1 KHz and the carrier frequency were 1 MHz, for example, then the output frequency will swing between a maximum of 1 MHz + 1 KHz and a minimum of 1 MHz - 1 KHz.

NOTE: If values for the deviation and carrier frequencies are entered such that the output frequency exceeds the 0 to 21.5 MHz range, distortion of the output waveform may result.

3. Carrier Frequency

In this field enter the frequency of the carrier. You may enter from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps. NOTE: If values for the deviation and carrier frequencies are entered such that the output frequency exceeds the 0

to 21.5 MHz range, distortion of the output waveform may result.

4. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in

0.1 dBm steps.

NOTE: The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O

load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage turns off the output. For further information on the Ext Gating Input, refer to section 2.0.

BK Precision 4070A User Manual Rev.2.2

External FM

Pk dev: 10,000 Hz

213

5.5 External FM Mode

Introduction

External FM mode generates frequency-modulated signal of fixed amplitude were externally supplied signal is used as a modulating signal to vary frequency of the carrier signal. Modulated frequency, level, peak deviation and DC offset values could be manually entered from the front panel keypad in this mode. External signal gating options is available in this mode. External FM mode could be entered by pressing “Mode”> “FM” >”2” key at any time

External FM Mode Parameters

The External FM mode has the following front panel display:

1,000,000.00 Hz -10.0 dBm

Figure 5.4-1: External FM mode display

1. Peak Frequency Deviation

In this field specify the degree to which the modulating signal is allowed to change the carrier frequency. You may enter from 0 Hz (no change) to 5.0 MHz in 1 Hz steps. This parameter is a peak value. If the deviation were 1 KHz and the carrier frequency were 1 MHz, for example, then the output frequency will swing between a maximum of 1 MHz + 1 KHz and a minimum of 1 MHz - 1 KHz for an input signal level of 1 Vp-p.

NOTE: If values for the deviation and carrier frequencies are entered such that the output frequency exceeds the 0 to 21.5 MHz range, distortion of the output waveform may result.

2. Carrier Frequency

to 21.5 MHz range, distortion of the output waveform may result.

3. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1 dBm steps.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage turns off the output. For further information on the Ext Gating Input, refer to section 2.0.

BK Precision 4070A User Manual Rev.2.2

nt PM: 1,000 Hz

Pk dev: 180 deg

123

5.6 Internal PM Mode

Introduction

Internal PM mode generates phase -modulated signal of fixed amplitude. It used internally generated signal to modulate phase of carrier signal. Modulated and modulating frequency, output level, deviation, and DC offset values could be manually entered on the keypad in this mode. External signal gating options is available in this mode. Internal PM mode could be entered by pressing “Mode”> “PM” >”1” key at any time.

Internal PM Mode Parameters

The Internal PM mode has the following front panel display:

1,000,000.00 Hz -10.0 dBm

Figure 5.6-1: Internal PM mode display

1. Modulating Frequency

In this field enter the frequency of the modulating sinusoid. You may enter from 0 Hz to 10,000 Hz in 1 Hz steps.

2. Peak Phase Deviation

In this field specify the degree to which the modulating signal is allowed to change the carrier phase. You may enter from 0 (no change) to 180 degrees in 1-degree steps. This parameter is a peak value. If the deviation value were 180 degrees, for example, then the output phase will advance to a maximum of +180 degrees and retard to a minimum of -180 degrees. To enter a value, type 1 to 3 numeric digits. If you type 3 digits, the value is automatically entered. If you only type 1 or 2 digits, you can press the MHz key or the KHz key or the Hz key (all are equivalent) to enter the degree value.

NOTE: FM modulation is equivalent to PM for small frequency deviation values. If you need a larger phase deviation than 180 degrees, go to FM mode and specify an appropriate peak frequency deviation value.

3. Carrier Frequency

In this field enter the frequency of the carrier. You may enter from 0 Hz (DC) to 21.5 MHz in 0.1 Hz steps.

4. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in

0.1 dBm steps. NOTE: The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O

load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage turns off the output. For further information on the Ext Gating Input, refer to se ction 2.0.

BK Precision 4070A User Manual Rev.2.2

External PM

Pk dev: 180 deg

213

5.7 External PM Mode

Introduction

External PM mode generates phase -modulated signal of fixed amplitude were externally supplied signal is used as a modulating signal to vary phase of the carrier signal. Modulated frequency, level, peak deviation and DC offset values could be manually entered from the front panel keypad in this mode. External signal gating options is available in this mode. External PM mode could be entered by pressing “Mode”> “PM” >”2” key at any time.

External PM Mode Parameters

The External PM mode has the following front panel display:

1,000,000.00 Hz -10.0 dBm

Figure 5.7-1: External PM mode display

1. Peak Phase Deviation

In this field specify the degree to which the modulating signal is allowed to change the carrier phase. You may enter from 0 degrees (no change) to 180 degrees in 1 degree steps. This parameter is a peak value. If the deviation value were 180 degrees, for example, then the output phase will advance to a maximum of +180 degrees and retard to a minimum of -180 degrees for a 1 Vp-p input signal. To enter a value, type 1 to 3 numeric digits. If you type 3 digits, the value is automatically entered. If you only type 1 or 2 digits, you can press the MHz key or the KHz key or the Hz key (all are equivalent) to enter the phase deviation value.

2. Carrier Frequency

In this field enter the frequency of the carrier. You may enter from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

3. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in

0.1 dBm steps. NOTE: The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O

load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage turns off the output. For further information on the Ext Gating Input, refer to section 2.0.

BK Precision 4070A User Manual Rev.2.2

St: 1,000,000.00 Hz

Stp: 20,000,000.00 Hz

1345672

5.8 Sweep Mode

Introduction

The Sweep mode continuously changes the frequency of a fixed amplitude sinusoid between a specified start frequency and stop frequency. The user can set sweep time as well. The frequency may be stepped between the start and stop frequency linearly. A sweep direction, up or down, could be specified. The user could choose continuous or triggered type sweep. In the Continuous mode, the sweep is restarted once the stop frequency reached. In the Triggered mode, the output waits at the start frequency until a trigger condition happens. Triggers can come from a front panel key press, a rising edge on the EXT Trigger connector, or an ASCII "T" on the terminal port. Once a trigger occurs, the output frequency is swept to the stop frequency and the sweep is then reset to the start frequency. The unit then awaits another trigger condition. For downward sweeps, the output frequency begins at the stop frequency and ends at the start frequency.

Sweep Mode Parameters

The Sweep mode has the following front panel display:

Linear | Cont | Up | Time: 60,000 mS -10.0 dBm

Figure 5.8-1: Sweep mode display

1. Start Frequency

In this field enter the starting frequency for the sweep. You may enter from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

NOTE: You are not allowed to enter a start frequency that is greater than the stop frequency.

2. Stop Frequency

In this field enter the ending frequency for the sweep. You may enter from 0 Hz to 21.5 MHz in 0.01 Hz steps. NOTE: You are not allowed to enter a stop frequency that is less than the start frequency.

3. Linear / Log sweep

In this field select how the sweep frequency is incremented during the sweep. A linear sweep means that the frequency is increm ented by a constant amount for a given amount of time. A log sweep means that the frequency is adjusted logarithmically between the start and stop frequencies as the sweep progresses. To set Linear type sweep, press 1. To set Log type sweep, press 0. Pressing any arrow key or rotating the wheel will toggle the sweep type between Linear and Log.

4. Continuous / Triggered sweep

In this field select whether the sweep is performed continuously or on a single event basis. If you select a Continuous sweep, then the sweep is immediately restarted once the stop frequency is reached. If you select a Triggered type sweep, then the sweep is halted once the stop frequency is reached. The sweep is not restarted again until another trigger occurs. The trigger can come from three sources:

1. Pressing the Trigger key

2. Applying a low -to-high transition on the Ext Trig In connector

3. Sending an ASCII "T" to the RS232 port The 4070A will simultaneously accept a trigger from all of the above sources. To set Continuous type sweep,

press 1. To set Triggered type sweep, press 0. Pressing any arrow key or rotating the wheel will toggle the sweep type between Continuous and Triggered.

BK Precision 4070A User Manual Rev.2.2

5. Up / Down sweep

In this field select the direction of the sweep. An up sweep begins at the start frequency and ends at the end frequency. A down sweep begins at the end frequency and ends at the start frequency. To set Up type sweep, press 0. To set down type sweep, press 1. Pressing any arrow key or rotating the wheel will toggle the sweep between Up and Down.

6. Sweep time

In this field you specify how long it takes the sweep to increase the frequency from the start frequency to the stop frequency. You may enter 1 mS to 60,000 mS (60 seconds) in 1 mS step. In Continuous sweep mode, the sweep may be halted by applying logic high to the Ext Gating Input connector on the rear of the unit. Doing so also halts the sweep timer, i.e. the sweep time will be lengthened by the amount of time that the sweep is halted.

7. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1 dBm steps.

Offset

You can enter an offset voltage for the output signal. For more information on output offsets refer to section 4.4.

SYNC Out Connector

This TTL/CMOS compatible output supplies a high going pulse at the start of each sweep. That could be useful for triggering scopes or other equipment at the start of each sweep.

Ext Gating Input

This TTL compatible input is used in two different ways, depending on whether the sweep mode is Continuous or Triggered. In Continuous sweep, the user can halt the sweep "dead in its tracks" by applying logic high (+3V to +10V) on this jack. The output frequency will be held constant until the input is brought low again. The sweep will then resume toward the stop frequency. In Triggered type sweep, this input functions as an external sweep trigger input. A logic low -to-high transition on this input will trigger the sweep. This input has an internal pull down resistor so that the input is held at a logic low when this input is left unconnected.

BK Precision 4070A User Manual Rev.2.2

Int FSK: 1,000 Hz

Mark: 1,000,000.00 Hz

132

5.9 Internal FSK Mode

Introduction

Internal FSK mode generates a frequency shift keyed signal of fixed amplitude. Internal timer is used as modulating signal to toggle the output signal frequency between mark frequency and space frequency. Mark and Space frequencies, output level, modulating shift frequency and DC offset values could be manually entered from the front panel keypad in this mode. External signal gating option is available in this mode. Internal FSK mode could be entered by pressing “Mode”> “FSK” >”1” key at any time.

Internal FSK Mode Parameters

The Internal FSK mode has the following front panel display:

Space: 2,000,000.00 Hz -10.0 dBm

Figure 5.9-1: Internal FSK mode display

1. Modulating Frequency

In this field enter the frequency at which the output will switch between the Mark and Space frequencies. You may enter from 0 Hz to 130,000 Hz in 1 Hz steps. The internal modulating frequency is accurate to 1 Hz from 0 Hz to 3900 Hz. It is accurate to within 1% across its full range of 0 Hz to 130,000 Hz.

2. Mark Frequency

In this field enter the Mark frequency, from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

3. Space Frequency

In this field enter the Space frequency, from 0 Hz (DC) to 21.5 MHz in 0.01 Hz steps.

4. Level

In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1 dBm steps.

NOTE: For wideband FSK (where the difference between Mark and Space frequencies is > 1.0 MHz), the output level may shift slightly between the mark and space frequencies. The 4070A has internal leveling circuitry, which is disabled in this mode, in order to offer higher FSK modulation rates.

NOTE : The level specified is a 50O loaded level. This is the level of the signal, which will appear across a 50O

load connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.

Offset

You can enter an offse t voltage for the output signal. For more information on output offsets refer to section 4.4.

Ext Gating Input

This TTL compatible input can be used to gate the output signal on or off. A logic high voltage turns off the output. For further information on the Ext Gating Input, refer to section 2.0.

BK Precision 4070A User Manual Rev.2.2

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