Unisource Corporation FG-7005C User manual

_

BENCH-TOP INSTRUMENT

FG-7002C / 5C
2MHz / 5MHz

Sweep Function Generator
Operation Manual

G

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WARRANTY
Warranty service covers a period of one year from the date of original purchase.
In case of technical failure within one year, our service center or sales outlet free of

charge will provide repair service.
We charge customers for repair after the one-year warranty period has been

expired. Provided that against any failure resulted from the user’s negligence,
natural disaster or accident, we charge you for repairs regardless of the warranty
period.

For more professional repair service, be sure to contact our service center or sales
outlet.

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Introduction

Thank you for purchasing our product, electronic measuring instruments
produced by us are high technology products made under strict quality control. We
guarantee their exceptional precision and utmost reliability. For proper use of the
product, please read this operation manual carefully.

Note

1. To fully maintain the precision and reliability of the product use it within the range
of standard setting (temperature 10 qC~35 qC, humidity 45%~85%)

2. After turning of power, please allow a pre-heating period of as long as some 30
minutes before use.

3. This equipment should be used with a triple line power cord for safety.

4. For quality improvement the exterior design and specification of the product can
be changed without prior notice.

5. If you have further questions concerning use, please contact our service center
or sales outlet

Safety Summary
Please take a moment to read these operating instructions thoroughly and

completely before operating this instrument. Pay particular attention to WARNINGS
used for conditions and actions that pose hazard to the user and CAUTIONS used
for conditions and actions that may damage the instrument.

Always to inspect the instrument and other accessories for any sign of damage

z

or abnormality before every use.

Never ground yourself and keep your body isolated from ground.

z

Never touch exposed wiring, connections or any live circuit conductors.

z

Do not install substitute parts or perform any unauthorized modification to the

z

instrument.

Use caution when working above 60V DC or 30V AC rms. Such voltages pose

z

a shock hazard.

z Remember that line voltage is present on some power input circuit points such

as on-off switches, fuse, power transformers, etc., even when the equipment is
turn off.

z Also, remember that high voltage may appear at unexpected points in defective

equipment.

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Safety Symbols

1. Protective earth (ground)

To identify any terminal which is intended for connection to
an external conductor for protection against electric shock
In case of a fault, or the terminal of a protective earth
(ground) electrode.

2

.

Functional earth terminal on the rear panel.

3 “IN” position of a bi-stable push control

To associate the “IN” position of a bi-stable push control
with the corresponding function.

4. “OUT” position of a bi-stable push control

To associate the “OUT” position of a bi-stable push control

with the corresponding function.

5. Alternation current

To indicate on the rating plate that the equipment is
Suitable for alternating current only to identify relevant
terminals.

6. Caution, risk of danger

7. Caution, risk of electric shock

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1. PRODUCT DESCRIPTION

1-1. Introduction ----------------------------------------------------------------- ( 6 )
1-2. Technical Specifications ------------------------------------------------- ( 6 )
1-3. Equipment Ratings -------------------------------------------------------- ( 8 )
1-4. Supplied Accessories ---------------------------------------------------- ( 8 )

2. INSTALLATION

2-1. Initial Inspection ----------------------------------------------------------- ( 9 )
2-2. Connecting Ac Power ---------------------------------------------------- ( 9 )
2-3. Cooling And Ventilation -------------------------------------------------- ( 9 )
2-4. Position ---------------------------------------------------------------------- ( 9 )
2-5. Warming-Up ---------------------------------------------------------------- ( 9 )

3. OPERATION

3-1. Controls, indicators and connectors ---------------------------------- ( 10 )
3-2 2. Operating instruction -------------------------------------------------- ( 13 )
3-3. Use As Function Generator --------------------------------------------- ( 13 )
3-4. Use As Pulse Generator ------------------------------------------------- ( 16 )
3-5-1. TTL/CMOS Output ----------------------------------------------------- ( 18 )
3-5-2. TTL/SYNC Output ----------------------------------------------------- ( 19 )
3-6. Use As FM Signal Generator ------------------------------------------- ( 19 )
3-7. External Control Of VCF ------------------------------------------------- ( 21 )
3-8. Programmed Frequency Selection ------------------------------------ ( 22 )
3-9. Use As Sweep Generator ----------------------------------------------- ( 22 )
3-10. Use As Externally Controlled Sweep Generator ----------------- ( 23 )
3-11. Use As External Frequency Counter -------------------------------- ( 23 )

CONTENTS

4. MAINTENANCE

4-1. Fuse Replacement -------------------------------------------------------- ( 25 )
4-2. Adjustment And Calibration --------------------------------------------- ( 25 )
4-3. Cleaning and decontamination ----------------------------------------- ( 25 )

5. OTHERS

5-1. Introduction ----------------------------------------------------------------- ( 25 )
5-2. Troubleshooting By Signal Substitution ------------------------------ ( 26 )
5-3. Troubleshooting By Signal Tracing ----------------------------------- ( 26 )
5-4. Amplifier Overload Characteristics ------------------------------------ ( 27 )
5-5. Amplifier Performance Evaluation Using Square Waves -------- ( 28 )
5-6. Testing Speakers And Impedance Networks ----------------------- ( 31 )
5-7. Digital Frequency Selection --------------------------------------------- ( 32 )
5-8. Additional Applications --------------------------------------------------- ( 32 )

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1. PRODUCT DESCRIPTION

1.1. Introduction

This instrument is the Most Versatile Signal Source used as FUNCTION
GENERATOR, SWEEP GENERATOR, PULSE GENERATOR and a FREQUENCY
COUNTER, offering a wide range of applications in both analog and digital
electronics such as engineering, manufacturing, servicing, education and hobbyist
fields.

VCF(voltage controlled frequency) produces precision sine, square and triangle
waves over the 0.02 Hz to 2 MHz; FG-7002C, 0.05Hz - 5MHz; FG-7005C
audible, audio, ultrasonic and RF applications. A continuously variable DC offset
allows the output to be injected directly into circuits at the correct bias level.

Variable symmetry of the output waveforms converts the instrument to a pulse
generator capable of generating rectangular waves or pulses, ramp or sawtooth
waves and skewed sine waves of variable duty cycle. The sweep generator offers
linear sweep with variable sweep rate and sweep width up to 100:1 frequency
change. The frequency response of any active or passive device up to Maximum
frequency of each model can be determined.

for sub-

1-2. Technical Specifications

 OUTPUT CHARACTERISTICS
Waveforms : Sine, Square, Triangle, Skewed Sine, Pulse, Ramp

Sawtooth, TTL Leveled Square, DC

CMOS Leveled Square(FG-7002C only)

Frequency Range : In 7 Range (1, 10, 100, 1K, 10K, 100K,1M)

FG-7002C; 0.02 Hz to 2 MHz

FG-7005C; 0.05 Hz to 5 MHz

Frequency Drift Accuracy: ±2% (1, 10, 100, 1K, 10K, 100K,1M Range )
Output Level : 20 Vpp in open circuit, 10 Vpp into 50 : Load
Output Impedance : 50 : ±5%
Attenuator : 20 dB fixed and continuously variable




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 WAVEFORM CHARACTERISTICS
Sine wave -Flatness : ± 3dB to 2MHz(FG-7002C),

5MHz(FG-7005C)

-Distortion : Less than 1% at 0.2 Hz to 100 KHz

Square wave -Rise and Fall Time : Less than 120 nS
Triangle wave -Linearity : More than 99% at 0.2 Hz to 100 KHz
TTL Output -Rise and Fall time : Less than 25 nS

-Output Level : TTL Level(H

CMOS Output -Rise and Fall Time : Less than 160 nS(Max. Out)
(FG-7002C only)

DUTY RATIO : 1:1 to 10 : 1

 SWEEP FUNCTION CHARACTERISTICS
Mode : Linear
Width : Variable from 1 : 1 to 100 : 1
Rate : 0.5 Hz to 50 Hz (20 mS to 2 S)
External VCF Input :
Input Voltage : 0 to 10 V
Input Impedance : Approx. 1K:

-Output Level : 4V to 15V ± 2V, Variable

2.4V, L 0.4V)

 FREQUENCY COUNTER CHARACTERISTICS
Display :

FG-7002C: 6 digit green LED, Gate time, MHz, KHz, Hz, mHz.
FG-7005C : 7 digit green LED, Gate time, MHz, KHz, Hz, mHz.

Frequency Range :

FG-7002C: 200 mHz to 50 MHz With Auto Range.
FG-7005C : 200 mHz to 100 MHz With Auto Range.

Accuracy : ±Time base Error ± 1 count
Time base : 10 MHz Crystal, ±20ppm
Input Sensitivity : 100 mVrms
Max. Input Voltage : 250 Vpp

 DIMENSION AND WEIGHT
Dimension : 240(W)x 270(D) x90(H)mm
Weight : Approx. 2.0Kg(FG-7002C), 3.0kg(FG-7005C)

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1-3. Equipment Ratings

z Power & Fuse Ratings

Input Voltage Fuse Power Max.

115VAC +/-10%, 50/60Hz F 0.5A 250V 15W

230VAC +/-10% , 50/60Hz

NOTE: AC Power is preset to 115V or 230V in factory according to the request

of customer. AC Power can be selected inside of unit.

z Operating Environment
TEMPERATURE : 0 °C to + 40 °C (Accuracy Specified at 23°C ± 5 °C)

HUMIDITY :up to 85% to 40°C without temperature extremes

causing condensation within the instrument.

z Storage Environment
TEMPERATURE : -20°C to +70°C
HUMIDITY : below 85% RH

z Overvoltage Category : CAT II,

F 0.2A 250V (FG-7002C)

F 0.25A 250V (FG-7005C)

15W

Performed on circuits directly connected to the low voltage installation.

z Insulation Category II: Portable equipment of local level.
z Pollution Degree : 2
z Protection to IEC 529: Ordinary

1-4. Supplied Accessories

z User’s Manual ---------------------------------------------------------------------------- 1
z BNC Cable ------------------------------------------------------------------------------ 1
z Power Cord ------------------------------------------------------------------------------ 1

z Spare Fuse ------------------------------------------------------------------------------- 1

** Specifications are subject to change without notice.

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2. INSTALLATION

2-1. Initial Inspection

This instrument was carefully inspected both mechanically and electrically before
shipment. It should be physically free of damage. To confirm this, the instrument
should be inspected for physical damage in transit. Also, check for supplied
accessories are present and correct.

2-2. Connecting AC Power

CAUTION

AC POWER OF THIS INSTRUMENT IS PRESET TO 115V OR 230V IN FACTORY
ACCORDING TO THE REQUEST OF CUSTOMER. BEFORE POWERING ON
THIS INSTRUMENT, CHECK AND MAKE SURE THE VOLTAGE OF THE
POWER SOURCE IS SAME WITH THE MARKING OF UNIT.

This instrument requires 230V AC or 115V AC (50-60 Hz) power socket with
protective earth contact (PE-contact). If is available only a power socket without PE­contact (so a 2-conductor ac power) then a power socket with PE-contact must be
installed before or the appliance should be provided with a PE-screw-terminal which
is not soluble by hand and not soluble before 2-conductor power lines.

2-3. Cooling and Ventilation
No special cooling and ventilation is required. However, the instrument should be
operated where the ambient temperature is maintained.

2-4. Position
This instrument is built as a bench-type instrument with rubber feet and tilt stand
in place. Stand-up angle can be adjusted by rotating angle of carrying handle.

2-5. WARMING-UP
Allow more than 30 minutes for the unit to warm up so that it is stabilized and ready
for use.

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3. OPERATION

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3-1. Controls, indicators and connectors

71411311 68

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FIG 1-1. FRONT PANEL OPERATOR’S CONTROLS(FG-7002C)

FIG 1-2. FRONT PANEL OPERATOR’S CONTROLS(FG-7005C,)

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LED DISPLAY. Displays Internal or External

Frequency.

INTERNAL/EXTERNAL SWITCH. PUSH IN : External Frequency

Counter.
PUSH OUT: Internal Frequency
Counter.

RANGE SWITCHES. Frequency Range Selector.

FUNCTION SWITCHES. Select Sine wave, Triangle Wave Or

Square Wave Output.

ATTENUATOR. Selects Output Level By -20 dB.
GATE TIME INDICATOR. Gate Time Is Selected Automatically By

Input Signal.

FREQUENCY DIAL.(Coarse,Fine) Controls Output Frequency in Selected

Range.

MHz, KHz , Hz, mHz INDICATOR. Indicates Unit of Frequency.
EXTERNAL COUNTER INPUT BNC. Used as an External Frequency

Counter.

SWEEP RATE CONTROL. On-Off Switch For Internal Sweep
Generator, Adjusts Sweep Rate Of
Internal Sweep Generator.

SWEEP WIDTH CONTROL. Pullout And Adjusts Magnitude Of

Sweep.

VCF INPUT BNC. Voltage Controlled Frequency Input
Permits External Sweep.
Frequency Control Sweep Rate Control
Should Be Off When Applying External
Voltage At This BNC.

SYMMETRY CONTROL. Adjust Symmetry Of Output

Waveform 1:1 to 10:1 With Push/Pull
Switch On.

TTL/CMOS CONTROL. Selects TTL Or CMOS Mode
Pull-out : CMOS Level Control, Push-

In: TTL Level.
TTL/CMOS OUTPUT BNC. TTL/CMOS Level Output.
DC OFFSET CONTROLS. Adds Positive or Negative DC

Component to Output Signal.

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MAIN OUTPUT BNC. Impedance 50 Ohm.

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AMPLITUDE CONTROL. Adjusts Output Level from 0 to 20 dB.
TILT STAND. Pull Out to Adjust Tilt.

POWER SWITCH. Push type switch. turning on the power

when pressed.

LOW PASS FILTER

VOLTAGE

115V ~

230V ~

S/N :

POWER MAX

FUSE

0.5A F

0.2A F

Made in Korea

10W
10W

FIG 2-1. REAR PANEL(FG-7002C)

VOLTAGE

115V ~
230V ~

S/N :

FUSE

0.5A F

0.2A F

POWER MAX

20W
20W

FIG 2-2. REAR PANEL(FG-7005C)
AC INLET For connection of the supplied AC power
Voltage Selector Switch For selecting AC Input Voltage
FUSE HOLDER. Replacing fuse with unscrewing.
Ground Terminal.

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3-2. Operating instruction
This instrument is capable of generating a wide variety of waveforms and counting
an external frequency with high resolution of 6 digits LED for FG-7002C (7digits
LED for FG-7005C). The most benefit and satisfaction can be gained from the
instrument by fully understanding its capabilities and versatility and becoming
familiar with operation procedure. One of the best ways to initially gain this
familiarization is to connect the generator to an oscilloscope. Observe the
waveforms and notice the effects of the various controls on the waveforms. Use this
manual as a reference until becoming accustomed to operating procedures.

3-3. Use As Function Generator.

1) Procedure
A. Connect AC power cord into receptacle on rear panel and plug into AC inlet.
B. To turn on equipment, push power on-off switch on.
C. To make sure that the output is symmetrical and unaffected by the sweep

generator, set the following controls as below.

CONTROLS POSITION
Sweep width OFF(push)
Symmetry OFF(push)
DC offset OFF(push)
Attenuator RELEASE(button out)
Counter INTERNAL(button out)

D. To select the desired frequency, set the Range Switch and FREQ. dial as

follows; The output frequency equals the FREQ. dial setting multiplied by the
Range Switch setting.
For example, a FREQ. dial setting of 0.6 and a Range switch setting of 10K
produces a 6 KHz output(.6x10 = 6K). A FREQ. dial setting of 2.0 and a
Range switch setting of 1M produces 2 MHz output(2.0x1M = 2M).

E. And also it can display the desired frequency by 6 digit LED

display(FG-7002C) – 7digit LED display for FG-7005C.

F. Select sine, square, or triangle wave output by pressing the corresponding

FUNCTION button. FIG 3. illustrates the output waveforms and their phase
relationships.

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G. Connect a cable from the 50: BNC to the point where it is desired to inject

the signal.

H. Adjust the 50: output to the desired amplitude with the AMPLITUDE control.

TTL Pulse 0V

Triangle 0V

Sine 0V

Square

FIG. 3 OUTPUT WAVEFORMS AND PHASE RELATIONSHIPS

I. A positive or negative DC component can be added to the signal at the 50:

BNC by use of the DC OFFSET control, as required by the circuit into which
the signal is being injected.

J. A fixed amplitude TTL square wave is available at the TTL OUT BNC on the

front panel. This signal is unaffected by the AMPLITUDE, ATTENUATOR or
DC OFFSET. TTL output is a square wave for use in digital circuits, even
though FUNCTION SWITCH is on sine or triangle wave.

2) Considerations

KNOWLEDGE OF THE FOLLOWING FACTORS IS ESSENTIAL FOR PROPER

0V

CAUTION

OPERATION OF THE INSTRUMENT:

A. The DC offset control can provide over ±10 volts open-circuited, or ± 5 volts

into 50: load. Remember that the combined signal swing plus DC offset is
also limited to ±10 V open-circuited, or ±5 V into 50:. Clipping occurs slightly
next page these levels. FIG 4. illustrates the various operating conditions

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encountered when using DC offset. If the desired output signal is large or if a
large DC offset is used, an oscilloscope should be used to make sure that the
desired combination is obtained without clipping. Keeping the Amplitude
control in the lower half of its adjustment range reduces the probability of
clipping.

B. To set the DC offset to zero or a specific DC voltage, depress the Function

Switches slightly so that all switches are released(all buttons out). This
removes signal from the output and leaves the DC only. Measure the DC
output on an oscilloscope or DC voltmeter and adjust the DC offset control for
the desired value.

C. It is easier to accurately set the FREQ. dial if settings between 0.1 and

2.0(FG-7002C), 5.0(FG-7005C),

are used. Since the dial rotation overlaps
ranges, it is not usually necessary to use readings below 1. Just change to a
lower range and use a higher dial setting.

+5V

A. Zero DC Offset
with maximum signal

B. Offset limits
without Clipping

C. Excessive Offset
all example
output terminated in 50

0V

-5V

+5V

0V

-5V

+5V

0V

-5V

Positive
DC Offset

Positive
DC Offset

Negative
DC Offset

Negative
DC Offset

FIG 4. USE OF DC OFFSET CONTROL

D. The main output BNC is labeled 50:. This means that the source impedance

is 50:, but the output may be fed into any circuit impedance. However, the
output level varies in proportion to the terminating impedance. If it is desired
to maintain a constant output level while injecting signal into various circuits
with various impedance, a constant terminating impedance is necessary.

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When the generator output is connected to a coaxial connector on the
equipment under test, it usually moderate to high impedance. A reasonably
constant terminating impedance may be maintained while injecting signal into
moderate and high impedance circuits(500: and up)by adding a coaxial tee
in the output cable and connecting a 50: termination to one leg. Remove the
50: termination when injecting into a 50: circuit. Also keep DC injection point,
the DC offset should be set to match the circuit voltage, or blocking capacitor
may be required to avoid DC loading with 50:.

E. When using the higher output frequencies and when using the square wave

output, terminate the cable in 50: to minimize ringing. Keep the cables as
short as possible.

F. To set output amplitude to a specific level, measure peak to peak amplitude on

an oscilloscope.

3-4. Use As Pulse Generator

In a symmetrical square wave, sine wave, or triangle wave, the positive and
negative transitions are of equal time duration, or 1:1 ratio. This is the condition
when the SYMMETRY control off. When the SYMMETRY control is pulled and
rotated, the positive transition can be stretched in relation to the negative transition,
up to at least, 10:1 ratio. Square waves can be stretched into rectangular waves or
pulses, triangle waves can be stretched into distorted wave shape called a skewed
sine wave. FIG 5. illustrates the types of waveforms possible and includes a
summary of control settings used to obtain the desired waveform.

1)Procedure
A. Setup generator as described for function generator operation. Display the

output of generator on an oscilloscope.

B. Select the desired type of waveform with the Function Switches. Press the

square wave button for pulses, triangle button for ramp waves or sine wave
button for skewed sine waves.

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Pulse

(Square)

Ramp

(Triangle)

Skewed
(Sine)

Adjust Period Of Shorter
Duration With Freq. Controls

TTL
SYNC

Adjust Period Of Longer

Duration With

Symmetry Controls

FIG 5. PULSE, RAMP, AND SKEWED SINE WAVE GENERATION

C. If both a specific pulse width and repetition rate (specific rise time and fall

time for ramp wave), :are required, The waveform may be obtained as
follows:

a. Adjust the shorter duration portion of the waveform(pulse width for pulse,

fall time for ramp waves)with the frequency controls FREQ. dial and
RANGE switch.

b. Adjust the longer duration portion of the waveform(rest time for pulses,

rise time for ramp waves)with the SYMMETRY control.

D. If a specific pulse width (specific fall time for ramp wave)is not critical, but a

specific repetition rate is required, the desired waveform may be obtained as
follows;

a. Observe the oscilloscope and adjust the SYMMETRY control to obtain

the approximate desired pulse width vs. rest time ratio(rise time vs. fall
time ratio for ramp waves).

b. Adjust the repetition rate with the frequency controls FREQ. dial and

RANGE switch. the frequency controls affect both the pulse width and
repetition rate.

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2) Considerations
A. When generating ramp waves or skewed sine waves, it may be easier to

measure the time periods on oscilloscope using the square wave mode, then
switch to the desired operating mode.

B. For ease and accuracy in measurement, use a higher sweep speed on the

oscilloscope to expand the pulse width for measurement, then reduce sweep
speed to measure the repetition rate.

C. Repetition rate may be expressed as a frequency or time period. Measure

the repetition rate as a time period on oscilloscope and convert to frequency
if required. The repetition rate includes the full cycle, both the pulse width
and rest time for pulses, the rise time and fall time for ramp waves.

D. Repetition rate can be measured accurately and easily as a frequency or

time period with a frequency counter.

E. Pulse width also can be measured on a frequency counter, but only with the

SYMMETRY control set off before the pulse waveform is “stretched”. Pulse
width equals one-half the time period of the square wave. If the counter is
not equipped for period measurement, calculate the frequency, which is
equivalent to the desired pulse width, and measure the frequency of the
waveform.

DESIRED FREQUENCY =

DESIRED PULSE WIDTH x 2

3-5-1. TTL/CMOS OUTPUT(FG-7002C only)

TTL/CMOS output is specifically designed for compatibility with TTL/CMOS digital
logic circuits. Set-up time is considerably reduced because the fixed logic levels
and polarity are ready for direct injection into TTL/CMOS circuits. there is a need for
protection from accidental Application of too high amplitude or incorrect DC offset
which might damage semiconductors. Another advantage is the extremely fast rise
time and fall time of signal. To use the TTL/CMOS output, connect a cable from
TTL/CMOS BNC on the Front panel to the point at which it is desired to inject the
signal. TL/CMOS output may be used in several modes of operation. Some
examples follow.

1

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A. Using the square wave generator or pulse generator modes, clock pulses can

be generated for testing, troubleshooting or circuit analysis. The instrument
could even be used as a substitute master clock generator as TTL/CMOS
circuits can be driven from the TTL/CMOS BNC.

B. The CMOS Level Control potentiometer (pull out position) provides CMOS

level output from 5V to 15V Variable and Continuously. For TTL/CMOS
output level, Rotate the potentiometer switch and Observe the TTL or CMOS
output : Push-in is TTL, Pull-out is CMOS.

3-5-2. TTL/SYNC OUTPUT (FG-7005C only)

TTL/SYNC output is specifically designed for compatibility with TTL SYNC digital
logic circuits. Set-up time is considerably reduced because the fixed logic levels
and polarity are ready for direct injection into TTL SYNC circuits. there is a need for
protection from accidental Application of too high amplitude or incorrect DC offset
which might damage semiconductors. Another advantage is the extremely fast rise
time and fall time of signal. To use the TTL SYNC output, connect a cable from TTL
SYNC BNC on the Front panel to the point at which it is desired to inject the signal.
TTL SYNC output may be used in several modes of operation. Some examples
follow.

A. Using the square wave generator or pulse generator modes, clock pulses

can be generated for testing, troubleshooting or circuit analysis. The
instrument could even be used as a substitute master clock generator as
TTL SYNC circuits can be driven from the TTL SYNC BNC.

3-6. Use As FM Signal Generator

1) Procedure

A. Set up equipment as described for function generator operation. Use the

frequency and amplitude controls to set the carrier to the desired frequency and
amplitude.

B. Connect an AC modulating signal with no DC component to the VCF IN BNC

on the front panel of generator.

C. Adjust amplitude of the AC modulating signal for the desired frequency

deviation.

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2) Considerations
A. The approximate frequency deviation for a given VCF IN signal can be

determined as follows, The 0.1 V change at the VCF IN BNC produces a
frequency change of 1% of the highest frequency obtainable on a given
range. For example(FG-7002C), the highest frequency obtainable on the 100
K range is 200 KHz. One percent of 200 KHz equals 2 KHz. Therefore, 0.1 V
change at the VCF IN BNC will deviate the output frequency 2 KHz on the
100K range. Following table summarizes the frequency deviation versus
VCF IN voltage for all ranges.

RANGE

1
10

100
1K
10K
100K

1M

Frequency deviation versus VCF IN voltage for each model.

B. For an example(FG-7002C), it is assumed that we wish to generate a 455

KHz signal with FM deviation of ±15 KHz (30 KHz swing). 1M range will be

used to obtain the 455 KHz carrier with the FREQ. dial set to 0.455. The

highest frequency obtainable on the 1M range is 2 MHz. One percent of 2

MHz is 20 KHz. Our requirement of 30 KHz deviation is 1.5 times greater

HIGHEST FREQ.

OBTAINABLE(Hz)

FG-7002C FG-7005C FG-7002C FG-7005C

2

20

200

2k

20k

200k

2M

5

50

500

5k

50k

300k

5M

FREQ. DEVIATION FOR EACH

0.1 VOLT VCF IN CHANGE(Hz)

0.02

0.2
2

20

200

2K

20K

0.05

0.5
5

50

500

5k

50k

than 20 KHz deviation produced by a 0.1 volt VCF IN swing, thus we will use

1.5 times as much peak-to-peak voltage swing or 0.15 V.

STATED ANOTHER WAY: SUBSTITUTING THIS EXAMPLE:

desired deviation
1% deviation 20 KHz

C. Remember that the value of VCF IN signal is the peak to peak amplitude.

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x0.1 V = required VCF IN signal

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30 KHz

x 0.1 = 1.5 x 0.1V = 0.15V

3-7. External Control Of VCF

Within a given range, the FREQ. dial setting normally controls the output
frequency of generator. However, applying voltage at the VCF IN BNC on the front
panel also may control it. There are three basic possible modes of external VCF
control as detailed below,

A. Applying an AC voltage produces FM modulation(previously described in

“Use as FM Signal Generator” paragraph.

B. Applying a specific fixed DC voltage will produce a specific output frequency

described in following “Programmed Frequency Selection”paragraph)

C. Applying a ramp voltage(or other type waveform if desired)provides externally

controlled sweep generator operation(described in following “Use as
Externally Controlled Sweep Generator” paragraph)

The following consideration apply to all modes of operation involving external
control of the VCF(voltage controlled frequency)

A. The output frequency of generator is determined by the voltage applied to the

VCF. First of all, this voltage is established by the setting of the FREQ. dial.
Any voltage input drives the VCF TO A HIGHER FREQUENCY. However.
The VCF can never be driven beyond its range limits (the highest and lowest
frequencies that can be attained with the dial on a given range.)

B. With the FREQ. dial set at minimum and 0 volts at the VCF in BNC, the

generator output frequency is at the lower limit of the selected range.
Increasing the voltage to + 10 volts drives the generator frequency to the
upper limit of the range. Between 0 and + 10 Volts, the generator output
frequency is proportional to the VCF IN voltage. The VCF IN voltage can be
correlated to equivalent dial settings as given in Table below.

VCF voltage

FG-7002C FG-7005C
0
1
2
3
4
5
6
7
8
9

10

Correlation between VCF IN voltage and equivalent dial setting(dial set to Min.)

Equivalent dial Setting

0.02

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0.05

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

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C. The FREQ. dial is usually set to 0.02 when using external VCF control. This

reduces the dialed VCF voltage to zero and allows the external VCF voltage
to exercise complete control. It also reduces the effects of dial setting
inaccuracy.

D. If the summed dial setting and VCF IN voltage exceeds +10 volts, oscillation

ceases and no output is produced. If the swing of the VCF IN signal is too great,
oscillation will cease each time the instantaneous voltage reaches the limit.

3-8. Programmed Frequency Selection

A specific output frequency can be selected each time a specific VCF input
voltage is applied(assuming a common dial setting). Such operation may
be advantageous where there is a requirement to return to a specific
frequency periodically. Eliminating the need for frequency measurement
reduces set-up time and precision tuning each time frequency is needed.
Just set the dial against its lower stop and turn on the external VCF voltage.
Using multiple DC voltage values, which may be selected by a switch or
electronic switching circuits, may program a set of two or more specific
frequencies. This type of operation would be desirable in production testing
where signals at several specific frequencies are required for various tests.
FSK(frequency shift keying)signals also may be generated in this manner.
To maintain the original accuracy each time the operation is repeated, the
FREQ. dial must be accurately set to the same position. Probably the
easiest way to assure this common dial setting is to
set it against its lower stop. Additional information on programmed
frequency selection is given in APPLICATIONS chapter of this manual.

3-9. Use As Sweep Generator

1) Procedure
A. Set up equipment as for function generator operation.
B. Select the highest frequency to be swept with RANGE switch and the

lowest frequency to be swept with FREQ. dial.
C. Adjust amount of sweep with the sweep rate control.
D. Adjust repetition rate of sweep with the sweep rate control.

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2) Considerations
Minimum FREQ. dial setting is recommended for most sweep generator
operation. The dial setting determines the lowest frequency of generator. The
sweep generator will sweep upward from that point. However, it will sweep
upward only to the range limit (highest frequency to which the dial can tune on
the selected range). Therefore, a low dial setting is required to obtain a sweep
covering a wide frequency range. The minimum dial setting must be used to
obtain the maximum sweep width of 100:1(highest frequency sweep is 100 times
that of lowest frequency swept).If a high dial setting and high SWEEP WIDTH
setting are used simultaneously, the generator will sweep to the range limit and
ceases operation for a portion of the sweep cycle, effectively clipping the sweep.
Of course, if only a small frequency band is to be swept, a low dial setting is not
important. In fact, it may be easier to set to the desired frequencies if the dial
setting is 0.1 or higher.

3-10. Use As Externally Controlled Sweep Generator

A ramp voltage, or any other type waveform desired, can be applied for externally
controlled sweep generator operation. 0 to 10 volt swing will sweep frequencies
over a 100:1 ratio(with dial set to minimum value) Set up the instrument as
described for internally controlled sweep generator operation, except turn the
SWEEP WIDTH control to OFF. Apply the sweep voltage with no DC component at
the VCF Input BNC. Set the FREQ. dial to the highest frequency to be swept and
apply a negative-going ramp voltage.

3-11. Use As External Frequency Counter

1) USE AS EXTERNAL FREQUENCY COUNTER
A. EXTERNAL AND INTERNAL COUNTER SELECTION

This instrument can be used as a counter by Push-in of INT/EXT

selection switch.
B. EXT COUNT IN BNC : accepts external frequency input.
C. COUNTER DISPLAY : Input frequency is displayed with high resolution

on a 6 digit LED display.

D. mHz, Hz, KHz, MHz INDICATOR: mHz, Hz, KHz, MHz indicators &

decimal points display the max. 50 MHz of external frequency.

E. PUSHED-IN FREQ.RANGE S.W X1.

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F. LOW PASS FILTER : If necessary, engage the LPF (low pass filter)

switch. This route the input through a low pass filter (-3 dB point of
approximately 100 KHz) before application to the frequency counter.
This helps eliminate counting errors in low frequency measurements
by minimizing effects of high frequency noise present on the input.

CAUTION

1. APPLICATION OF INPUT VOLTAGES HIGHER THAN THE LIMITS LISTED IN
THE SPECIFICATIONS SECTION MAY DAMAGE THE COUNTER. BEFORE
APPLYING ANY SIGNAL TO THE INPUTS, MAKE CERTAIN THAT IT DOES NOT
EXCEED THESE SPECIFIED MAXIMUMS.

2. FREQUENCY COUNTER GROUND POINTS ARE CONNECTED DIRECTLY TO
EARTH GROUND. ALWAYS CONNECT FREQUENCY COUNTER GROUND
ONLY TO GROUND POINTS IN THE CIRCUIT UNDER TEST

NOTE

THE OVERVOLTAGE CATEGORY OF EXTERNAL FREQUENCY INPUT
TERMINAL IS “CAT II”. IT IS PERFORMED ON CIRCUITS DIRECTLY
CONNECTED TO THE LOW VOLTAGE INSTALLATION.

4. MAINTENANCE
CAUTION

IT IS ESSENTIAL FOR SAFETY TO PROPERLY MAINTAIN AND SERVICE THIS
INSTRUMENT

WARNING

VOLTAGES WITHIN THIS INSTRUMENT ARE SUFFICIENTLY HIGH TO
ENDANGER LIFE. COVERS MUST NOT BE REMOVED EXCEPT BY PERSONS
QUALIFIED AND AUTHORIZED TO DO SO AND THESE PERSONS SHOULD
ALWAYS TAKE EXTREME CARE ONCE THE COVERS HAVE BEEN REMOVED.

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4-1. Fuse replacement

Disconnect and remove all connections from any live power source.

z

Unscrew fuse holder by screw driver.

z

Locate the defective fuse and remove it by gently pulling-out.

z

Install a new fuse of the SAME SIZE AND RATING.

z

Screwing fuse holder.

z

CAUTION

MAKE SURE THAT THE RATED AND SPECIFIED FUSES ARE USED FOR
REPLACEMENT.

4-2. Adjustment and calibration
It is recommendable to regularly adjust and calibrate this instrument. Qualified and
authorized personnel only should execute performance and procedures

4-3. Cleaning and decontamination
The instrument can be cleaned with a soft clean cloth to remove any oil, grease or
grime. Never use liquid solvents or detergents. If the instrument gets wet for any
reason, dry the instrument using low pressure clean air at less than 25 PSI. Use
care and caution around the window cover areas where water or air could enter into
the instrument while drying.

5. OTHERS

5-1. Introduction
Because of the great versatility of this Sweep/Function Generator, it would be
impossible to include all of its possible applications in this manual, However ,many
of the primary applications are described in detail to allow the user to adapt the
procedures to other applications. The instrument has vast numbers of applications
as a signal source in electronics design labs, classrooms, service shops and
production facilities to test or analyze audio, radio, digital, communications, medical
electronics, sonar, industrial electronics, subsonic, ultrasonic and many other
electronic devices and circuits.

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5-2. Troubleshooting By Signal Substitution
When troubleshooting dead audio equipment, localize the trouble by injecting an
audio signal from Sweep/Function Generator to substitute for the normal signal.
Starting at the nearest speaker and moving toward the audio input area, Step By
Step, sound will be heard from the speaker for each stage that is operating normally.
When signal is applied to the defective stage, no sound will be heard from the
speaker.

CAUTION

MAKE SURE THE DC OFFSET MATCHES THE NORMAL OPERATING
VOLTAGE AT EACH POINT OF SIGNAL INJECTION. IMPROPER DC OFFSET
COULD BIAS A NORMALLY OPERATING STAGE TO CUT OFF AND MAKE IT
APPEAR DEFECTIVE. IMPROPER DC OFFSET COULD ALSO DAMAGE
CERTAIN CIRCUITS. A COUPLING CAPACITOR MAY BE USED TO BLOCK THE
DC OFFSET AND ALLOW THE SIGNAL TO FLOAT AT THE DC LEVEL OF THE
POINT OF INJECTION IF DESIRED.

The signal amplitude should also simulate the normal signal levels used in the
circuit where signal is being injected. This technique is equally applicable to non
audio equipment. Just connect an oscilloscope, voltmeter, or any other device,
which will indicate the presence or absence of output. Inject the type of signal
normally used by the equipment being tested. This instrument can generate almost
any type of signal normally required in the frequency range
2MHz, FG-7005C: 0.05Hz to 5MHz). If the equipment under test, It can generate
unique sounds or signals by means of sweep that should be easily distinguishable
from any other signals that may be present.

(FG-7002C:0.02Hz to

5-3. Troubleshooting By Signal Tracing

This technique is similar to “Troubleshooting by Signal Substitution” except that the
signal is injected at the input of the equipment under test. An oscilloscope is then
used to check for output at each stage, starting nearest at the input area and
moving toward to the output area. Each stage, which has no output, is presumed to
be defective.

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5-4. Amplifier Overload Characteristics

The overload point for some amplifiers is difficult to determine by using sinewave
input. The triangle waveform is ideal for this type of test because any departure
from absolute linearity is readily detectable. By using the triangle output, the peak
overload condition for an amplifier can be readily determined. This overload
condition is shown in shown in FIG 6.

Input Waveform

Output Waveform

FIG 6. Amplifier overload characteristics

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5-5. Amplifier Performance Evaluation Using Square Waves

The standard sinewave frequency reopens curves do not give a full evaluation of
the amplifier transient response. the square wave, because of the high harmonic
content, yields much information regarding amplifier performance when used in
conjunction with an oscilloscope.

A. Use the test set-up of FIG 7. The 50: termination at the amplifier input is

essential when using square waves to eliminate the ringing effects generated
by the fast rise times.

B. Using the triangle output, set the AMPLITUDE control so that there is no signal

clipping over the range of frequencies to be used.

C. Select the square wave output and adjust the frequency to several check

points within the pass band of the amplifier such as 20 Hz, 1000 Hz and 10
KHz.

D. At each frequency checkpoint, the waveform obtained at the amplifier output

provides information regarding amplifier performance with respect to the
frequency of square wave input. FIG 7. indicates the possible waveforms
obtained at the amplifier output. Square wave evaluation is not practical for
narrow-band amplifiers. The restricted bandwidth of the amplifier cannot
reproduce all frequency components of the square wave in the proper phase
and amplitude relationships.

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Square Wave Selected

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FIG 7. AMPLIFIER PERFORMANCE EVALUATION USING SQUARE WAVES.

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A. Test Set-up

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GENERATOR

C. Graph Of Results

FIG 8. TESTING SPEAKER SYSTEMS AND IMPEDANCE NETWORKS.

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5-6. Testing Speakers and Impedance Networks

This instrument can be used to provide information regarding the input impedance
of a speaker or any other impedance network vs. frequency. In addition, the
resonant frequency of the network can be determined.

A. Connect equipment as shown in Test Set-Up in FIG. 8 for frequency

response measurement except that the signal input to the speaker or
impedance network is monitored. The oscilloscope may be used to verify that
this instrument is not in a clipping condition.

B. If the voltmeter method is used, vary the range over the full range of interest

and log the voltage measured at the speaker terminals vs. Frequency. The dB
scales of the AC voltmeter are convenient for converting this information to
standard response units.

C. If the oscilloscope method is used, use sweep operation as for frequency

response measurement.

D. In speaker testing, a pronounced increase of voltage will occur at some low

frequency. This is the resonance frequency of the speaker systems(FIG. 8).
The speaker enclosure will modify the results obtained from the same
speaker without an enclosure. A properly designed enclosure will produce a
small peak on each side of the peak obtained without an enclosure. the
enclosure designer can use the response characteristics to evaluate the
effects of varying port sizes, damping materials and other basic enclosure
factors.

E. In testing other impedance networks resonance will not necessarily occur at

low frequency. However, as resonance is approached the signal level will
increase. The impedance of the network can be measured at resonance, or at
other frequencies if desired as follows:

1) Connect a variable resistor in series with the impedance network as
shown in FIG. 8

2) Measure the voltage at points E1 and E2 respectively and adjust variable
resistor R1 so that voltage E2 equals one half of voltage E1

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5-7. Digital Frequency Selection

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Frequencies can be switched electronically by using the set-up shown in FIG. 9.
The preset voltages can be digitally selected and applied to the VCF IN BNC.
Although provision for two frequencies are shown, additional frequencies can be
added using redundant circuits. This is convenient in frequency shift keying(FSK)
systems.

FIG 9. DIGITALLY PROGRAMMED FREQUENCY SELECTION

5-8. Additional Applications

The triangle or ramp output of this instrument can be used at its lowest frequencies
to simulate a slowly varying DC source. This can be used to check threshold levels
of TTL and CMOS logic as well as voltage compactors can be exercised from zero
to full scale to observe defective deflection such as sticky meter movements.

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This is marking shown on the product or its literature, indicates that it should

p

not be disposed with other household wastes at the end of its working life.
To prevent possible harm to the environment or human health from
uncontrolled waste disposal, please separate this from other types of wastes

and recycle it responsibly to promote the sustainable reuse of material resources.

Household users should contact either the retailer where they purchased this product, or
their local government office, for details of where and how they can take this item for
environmentally safe recycling.

Business users should contact their supplier and check the terms and conditions of the
purchase contract.
This

roduct should not be mixed with other commercial wastes for disposal.

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{GGGGGGGU

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