Wavetek 39A Service Manual

MAINTENANCE MANUAL
Model 39A
40MHz Arbitrary Waveform Generator
October 2005 - Issue 1
This document contains information proprietary to Wavetek and is provided solely for instrument operation and maintenance. The information in this document may not be duplicated in any manner without the prior approval in writing from Wavetek.
Wavetek-Datron Test and Measurement Division
Hurricane Way Norwich Norfolk NR6 6JB, U.K.
Tel: 44 1603 256600 Fax: 44 1603 256688

Table of Contents

Specifications 2
Safety 10
Installation 11
General 12
Circuit Descriptions 13
Calibration 18
Parts List 21
Component Layouts 29
Circuit Diagrams 31
1
Note: This specification covers the whole series which includes 2- and 4- channel instruments;
the interchannel specifications only apply to the multi-channel instruments.
Specifications apply at 1828ºC after 30 minutes warmup, at maximum output into 50

WAVEFORMS

Standard Waveforms

Sine, square, triangle, DC, positive ramp, negative ramp, sin(x)/x, pulse, pulse train, cosine, haversine and havercosine.

Sine, Cosine, Haversine, Havercosine

Range: 0.1mHz to 16 MHz
Resolution: 0.1mHz or 7 digits
Accuracy: 10 ppm for 1 year
Temperature Stability: Typically <1 ppm/ºC.

Specifications

Output Level:
Harmonic Distortion: <0.1% THD to 100kHz; <–65dBc to 20kHz
<–50dBc to 1MHz,
Nonharmonic Spurii:

Square

Range: 1mHz to 16MHz
Resolution: 1mHz (4 digits)
Accuracy: ± 1 digit of setting
Output Level:
Rise and Fall Times: <25ns

Triangle

Range: 0.1mHz to 100kHz
Resolution: 0.1mHz or 7 digits
2.5mV to 10Vpp into 50
<35dBc to 10MHz
<30dBc to 16MHz
<–65dBc to 1MHz, <–65dBc + 6dB/octave 1MHz to 16MHz
2.5mV to 10Vpp into 50
Accuracy: 10 ppm for 1 year
Output Level:
Linearity Error: <0.1% to 30 kHz

Ramps and Sin(x)/x

Range: 0.1mHz to 100kHz
Resolution: 0.1mHz (7 digits)
Accuracy: 10 ppm for 1 year
Output Level:
Linearity Error: <0.1% to 30 kHz
2
2.5mV to 10Vpp into 50
2.5mV to 10Vpp into 50

Pulse and Pulse Train

Output Level: 2.5mV to 10Vpp into 50
Rise and Fall Times: <25ns
Period:
Range: 100ns to 100s Resolution: 4-digit Accuracy: ±1 digit of setting
Delay:
Range: 99.99s to +99.99s Resolution: 0.002% of period or 25ns, whichever is greater
Width:
Range: 25ns to 99.99s Resolution: 0.002% of period or 25ns, whichever is greater
Note that the pulse width and absolute value of the delay may not exceed the pulse period at any time.
Pulse trains of up to 10 pulses may be specified, each pulse having independently defined width, delay and level. The baseline voltage is separately defined and the sequence repetition rate is set by the pulse train period.

Arbitrary

Up to 100 user defined waveforms may be stored in the 256K point nonvolatile RAM. Waveforms can be defined by front panel editing controls or by downloading of waveform data via RS232 or GPIB.
Waveform Memory Size: 64k points per channel. Maximum waveform size is 64k
Vertical Resolution: 12 bits
Sample Clock Range: 100mHz to 40MHz
Resolution: 4 digits
Accuracy: ± 1 digit of setting

Sequence

Up to 16 waveforms may be linked. Each waveform can have a loop count of up to 32,768.
A sequence of waveforms can be looped up to 1,048,575 times or run continuously.

Output Filter

Selectable between 16MHz Elliptic, 10MHz Elliptic, 10MHz Bessel or none.
points, minimum waveform size is 4 points
3
OPERATING MODES Triggered Burst
Each active edge of the trigger signal will produce one burst of the waveform.
Carrier Waveforms: All standard and arbitrary Maximum Carrier Frequency: The smaller of 1MHz or the maximum for the selected
Number of Cycles: 1 to 1,048,575
Trigger Repetition Rate: 0.005Hz to 100kHz internal
Trigger Signal Source: Internal from keyboard, previous channel, next channel or
External from TRIG IN or remote interface.
waveform. 40Msamples/s for ARB and Sequence.
dc to 1MHz external.
trigger generator.

Gated

Sweep

Trigger Start/Stop Phase:
Waveform will run while the Gate signal is true and stop while false.
Carrier Waveforms: All standard and arbitrary.
Maximum Carrier Frequency: The smaller of 1MHz or the maximum for the selected
Trigger Repetition Rate: 0.005Hz to 100kHz internal
Gate Signal Source: Internal from keyboard, previous channel, next channel or
Gate Start/Stop Phase:
Frequency sweep capability is provided for both standard and arbitrary waveforms. Arbitrary waveforms are expanded or condensed to exactly 4096 points and DDS techniques are used to perform the sweep.
Carrier Waveforms: All standard and arbitrary except pulse, pulse train and sequence.
± 360° settable with 0.1° resolution, subject to waveform frequency and type.
waveform.
dc to 1MHz external.
trigger generator.
External from TRIG IN or remote interface.
± 360° settable with 0.1° resolution, subject to waveform frequency and type.
40Msamples/s for ARB and Sequence.
4
Sweep Mode: Linear or logarithmic, triggered or continuous.
Sweep Direction: Up, down, up/down or down/up.
Sweep Range: From 1mHz to 16 MHz in one range. Phase continuous.
Independent setting of the start and stop frequency.
Sweep Time: 30ms to 999s (3 digit resolution).
Marker: Variable during sweep.
Sweep Trigger Source: The sweep may be free run or triggered from the following
sources: Manually from keyboard. Externally from TRIG IN input or remote interface.
Sweep Hold: Sweep can be held and restarted by the HOLD key.
Multi channel sweep: Any number of channels may be swept simultaneously but the
sweep parameters will be the same for all channels. Amplitude, Offset and Waveform can be set independently for each channel.

Tone Switching

Capability provided for both standard and arbitrary waveforms. Arbitrary waveforms are expanded or condensed to exactly 4096 points and DDS techniques are used to allow instantaneous frequency switching.
Carrier Waveforms: All waveforms except pulse, pulse train and sequence.
Frequency List: Up to 16 frequencies from 1mHz to 10MHz.
Trigger Repetition Rate: 0.005Hz to 100kHz internal
Source: Internal from keyboard, previous channel, next channel or trigger
Tone Switching Modes:
Gated:
The tone is output while the trigger signal is true and stopped, at the
dc to 1MHz external.
Usable repetition rate and waveform frequency depend on the tone switching mode.
generator.
External from TRIG IN or remote interface.
end of the current waveform cycle, while the trigger signal is false. The next tone is output when the trigger signal is true again.
Triggered:
The tone is output when the trigger signal goes true and the next
tone is output, at the end of the current waveform cycle, when the trigger signal goes true again.
FSK: The tone is output when the trigger signal goes true and the next
tone is output, immediately, when the trigger signal goes true again.
Using 2 channels with their outputs summed together it is possible to generate DTMF test signals.

Trigger Generator

Internal source 0.005 Hz to 100kHz square wave adjustable in 10us steps. 3 digit resolution. Available for external use from any SYNC OUT socket.

OUTPUTS

Main Output - One for each channel

Output Impedance:
Amplitude:
50
5mV to 20Vpp open circuit (2.5mV to 10Vpp into 50). Amplitude can be specified open circuit (hi Z) or into an assumed load of 50 or 600 in Vpkpk, Vrms or dBm.
Amplitude Accuracy:
Amplitude Flatness: ±0.2dB to 200 kHz; ±1dB to 10 MHz; ±2.5dB to 16 MHz.
DC Offset Range:
DC Offset Accuracy: Typically 3% ±10mV, unattenuated.
Resolution: 3 digits or 1mV for both Amplitude and DC Offset.
2% ±1mV at 1kHz into 50Ω.
±10V.DC offset plus signal peak limited to ±10V from 50.
5

Sync Out - One for each channel

Multifunction output user definable or automatically selected to be any of the following:
Waveform Sync:
(all waveforms) A square wave with 50% duty cycle at the main waveform frequency, or
a pulse coincident with the first few points of an arbitrary waveform.
Position Markers:
(Arbitrary only) Any point(s) on the waveform may have associated marker bit(s) set
high or low.
Burst Done: Produces a pulse coincident with the last cycle of a burst.
Sequence Sync: Produces a pulse coincident with the end of a waveform sequence.
Trigger: Selects the current trigger signal. Useful for synchronizing burst or
gated signals.
Sweep Sync: Outputs a pulse at the start of sweep to synchronize an oscilloscope or
recorder.
Phase Lock Out: Used to phase lock two generators. Produces a positive edge at the 0°
phase point.
Output Signal Level:

Cursor/Marker Out

Adjustable output pulse for use as a marker in sweep mode or as a cursor in arbitrary waveform editing mode. Can be used to modulate the Zaxis of an oscilloscope or be displayed on a second ‘scope channel.
Output Signal Level: Adjustable from nominally 2V to 14V, normal or inverted; adjustable
Output Impedance:
INPUTS Trig In
Frequency Range:
Signal Range: Threshold nominally TTL level; maximum input ±10V.
Minimum Pulse Width: 50ns, for Trigger and Gate modes; 50us for Sweep mode.
Polarity: Selectable as high/rising edge or low/falling edge.
Input Impedance:

Modulation In

TTL/CMOS logic levels from typically 50Ω.
width as a cursor.
600 typical
DC 1MHz.
10k

Sum In

6
Frequency Range: DC – 100kHz.
Signal Range:
SCM: Approximately ± 1Vpk for maximum output.
Input Impedance:
Frequency Range:
Signal Range:
Input Impedance:
VCA: Approximately 1V pkpk for 100% level change at maximum output.
Typically 1 kΩ.
DC 8 MHz.
Approximately 2 Vpkpk input for 20Vpkpk output.
Typically 1kΩ.

Hold

Holds an arbitrary waveform at its current position. A TTL low level or switch closure causes the waveform to stop at the current position and wait until a TTL high level or switch opening which allows the waveform to continue. The front panel MAN HOLD key or remote command may also be used to control the Hold function. While held the front panel MAN TRIG key or remote command may be used to return the waveform to the start. The Hold input may be enabled independently for each channel.
Input Impedance:
10k

Ref Clock In/Out

Set to Input: Input for an external 10MHz reference clock. TTL/CMOS threshold
level.
Set to Output: Buffered version of the internal 10MHz clock. Output levels nominally
1V and 4V from 50Ω.
Set to Phase Lock: Used together with SYNC OUT on a master and TRIG IN on a slave to
synchronise (phase lock) two separate generators.

INTER-CHANNEL OPERATION

Inter-channel Modulation:

The waveform from any channel may be used to Amplitude Modulate (AM) or Suppressed Carrier Modulate (SCM) the next channel. Alternatively any number of channels may be Modulated (AM or SCM) with the signal at the MODULATION input socket.
Carrier frequency: Entire range for selected waveform.
Carrier waveforms: All standard and arbitrary waveforms.
Modulation Types:
AM: Double sideband with carrier.
SCM: Double sideband suppressed carrier.
Modulation source: Internal from the previous channel.
External from Modulation input socket.
The external modulation signal may be applied to any number of
channels simultaneously.
Frequency Range: DC to >100 kHz.
Internal AM:
Depth: 0% to 105%
Resolution: 1%.
Carrier Suppression (SCM):
External Modulation Signal Range:
SCM: Approximately ± 1Vpk for maximum output.
> 40dB.
VCA: Approximately 1V pkpk for 100% level change at maximum output.
7

Inter-channel Analog Summing:

Waveform Summing sums the waveform from any channel into the next channel. Alternatively any number of channels may be summed with the signal at the SUM input socket.
Carrier frequency: Entire range for selected waveform.
Carrier waveforms: All standard and arbitrary waveforms.
Sum source: Internal from the previous channel.
External from SUM IN socket.
Frequency Range: DC to >8MHz.
External Signal Range:

Inter-channel Phase locking:

Two or more channels may be phase locked together. Each locked channel may be assigned a phase angle relative to the other locked channels. Arbitrary waveforms and waveform sequences may be phase locked but certain constraints apply to waveform lengths and clock frequency ratios. With one channel assigned as the Master and other channels as Slaves a frequency change on the master will be repeated on each slave thus allowing multi−phase waveforms at the same frequency to be easily generated.
DDS waveforms are those with 7 digits of frequency setting resolution, while NonDDS waveforms have 4 digits
Phase Resolution:
DDS waveforms: 0.1 degree
NonDDS waveforms:
Phase Error:
All waveforms: <±10ns
The signals from the REF IN/OUT socket and the SYNC OUT socket can be used to phase lock two instruments where more than 4 channels are required.

Inter-channel Triggering:

Approximately 5Vpkpk input for 20Vpkpk output.
0.1 degree or 360 degrees/number of points whichever is the greater.
Any channel can be triggered by the previous or next channel.
The previous/next connections can be used to ’daisy chain’ a trigger signal from a ‘start’ channel, through a number of channels in the ‘chain’ to an ‘end’ channel. Each channel receives the trigger out signal from the previous (or next) channel, and drives its selected trigger out to the next (or previous) channel. The ‘end’ channel trigger out can be set up to drive the ‘start’ channel, closing the loop.
In this way, complex and versatile interchannel trigger schemes may be set up. Each channel can have its trigger out and its output waveform set up independently. Trigger out may be selected from Waveform End, Position Markers, Sequence Sync or Burst Done.
Using the scheme above it is possible to create a sequence of up to 64 waveform segments, each channel producing up to 16 segments and all channels being summed to produce the complete waveform at the output of channel 4.

INTERFACES

Full remote control facilities are available through the RS232 or GPIB interfaces.
RS232:
IEEE488:
Variable Baud rate, 9600 Baud maximum. 9pin Dconnector.
Conforms with IEEE488.1 and IEEE488.2
8

GENERAL

Display: 20 character x 4 row alphanumeric LCD.
Data Entry: Keyboard selection of mode, waveform etc.; value entry direct by
numeric keys or by rotary control.
Stored Settings:
Size: 3U (130mm) height; 350mm width (2 and 4 channels),
Weight: 7.2 kg. (16 lb), 2 and 4 channels; 4.1kg (9lb) 1 channel.
Power: 230V, 115V or 100V nominal 50/60Hz, adjustable internally;
Operating Range:
Storage Range:
Environmental: Indoor use at altitudes up to 2000m, Pollution Degree 2.
Options: 19 inch rack mounting kit.
Safety:
EMC:
Up to 9 complete instrument setups may be stored and recalled from batterybacked memory. Up to 100 arbitrary waveforms can also be stored independent of the instrument settings.
212mm (½rack) single channel; 335mm long.
operating range ±14% of nominal; 100VA max. for 4 channels, 75VA max. for 2 channel, 40VA max. for 1 channel. Installation Category II.
+5°C to 40°C, 2080% RH.
20°C to + 60°C.
Complies with EN610101.
Complies with EN500811 and EN500821.
9

Safety

This generator is a Safety Class I instrument according to IEC classification and has been designed to meet the requirements of EN610101 (Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use). It is an Installation Category II instrument intended for operation from a normal single phase supply.
This instrument has been tested in accordance with EN610101 and has been supplied in a safe condition. This instruction manual contains some information and warnings which have to be followed by the user to ensure safe operation and to retain the instrument in a safe condition.
This instrument has been designed for indoor use in a Pollution Degree 2 environment in the temperature range 5°C to 40°C, 20% 80% RH (noncondensing). It may occasionally be subjected to temperatures between +5° and 10°C without degradation of its safety. Do not operate while condensation is present.
Use of this instrument in a manner not specified by these instructions may impair the safety protection provided. Do not operate the instrument outside its rated supply voltages or environmental range.
WARNING! THIS INSTRUMENT MUST BE EARTHED
Any interruption of the mains earth conductor inside or outside the instrument will make the instrument dangerous. Intentional interruption is prohibited. The protective action must not be negated by the use of an extension cord without a protective conductor.
When the instrument is connected to its supply, terminals may be live and opening the covers or removal of parts (except those to which access can be gained by hand) is likely to expose live parts. The apparatus shall be disconnected from all voltage sources before it is opened for any adjustment, replacement, maintenance or repair.
Any adjustment, maintenance and repair of the opened instrument under voltage shall be avoided as far as possible and, if inevitable, shall be carried out only by a skilled person who is aware of the hazard involved.
If the instrument is clearly defective, has been subject to mechanical damage, excessive moisture or chemical corrosion the safety protection may be impaired and the apparatus should be withdrawn from use and returned for checking and repair.
Make sure that only fuses with the required rated current and of the specified type are used for replacement. The use of makeshift fuses and the shortcircuiting of fuse holders is prohibited.
This instrument uses a Lithium button cell for nonvolatile memory battery backup; typical life is 5 years. In the event of replacement becoming necessary, replace only with a cell of the correct type, i.e. 3V Li/Mn0 in accordance with local regulations; do not cut open, incinerate, expose to temperatures above 60°C or attempt to recharge.
Do not wet the instrument when cleaning it and in particular use only a soft dry cloth to clean the LCD window. The following symbols are used on the instrument and in this manual:
20mm button cell type 2032. Exhausted cells must be disposed of carefully
2
Caution refer to the accompanying documentation, incorrect operation may damage the instrument.
10
l
terminal connected to chassis ground.
mains supply OFF.
mains supply ON.
alternating current.

Mains Operating Voltage

Check that the instrument operating voltage marked on the rear panel is suitable for the local supply. Should it be necessary to change the operating voltage, proceed as follows:
1) Disconnect the instrument from all voltage sources.
2) Remove the screws which retain the top cover and lift off the cover.
3) Change the transformer connections following the diagram below.
4) Refit the cover and the secure with the same screws.
5) To comply with safety standard requirements the operating voltage marked on the rear panel must be changed to clearly show the new voltage setting.
6) Change the fuse to one of the correct rating, see below.

Installation

Fuse

Ensure that the correct mains fuse is fitted for the set operating voltage. The correct mains fuse types are:
To replace the fuse, disconnect the mains lead from the inlet socket and withdraw the fuse drawer below the socket pins. Change the fuse and replace the drawer.
The use of makeshift fuses or the shortcircuiting of the fuse holder is prohibited.

Mains Lead

When a three core mains lead with bare ends is provided it should be connected as follows:
Any interruption of the mains earth conductor inside or outside the instrument will make the instrument dangerous. Intentional interruption is prohibited. The protective action must not be negated by the use of an extension cord without a protective conductor.

Mounting

This instrument is suitable both for bench use and rack mounting. It is delivered with feet for bench mounting. The front feet include a tilt mechanism for optimal panel angle.
for 230V operation connect the live (brown) wire to pin 15 for 115V operation connect the live (brown) wire to pin 14 for 100V operation connect the live (brown) wire to pin 13
for 230V operation: 250 mA (T) 250V HRC for 100V or 115V operation: 500 mA (T) 250V HRC
Brown
Blue
Green / Yellow
WARNING! THIS INSTRUMENT MUST BE EARTHED
Mains Live
Mains Neutral
Mains Earth
A rack kit for mounting in a 19” rack is available from the Manufacturers or their overseas agents.
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