DS335 Synthesized Function Generator

Calibration 4-19
NECESSARY EQUIPMENT
The following equipment is necessary to complete the adjustments and
calibrations. The suggested equipment or its equivalent may be used.
Instrument Critical Specifications Recommended Model
Analog Oscilloscope 350 MHz Bandwidth Tektronix 2465
Time Interval Counter Frequency Range: 20 MHz min. SRS SR620
Time Interval Accuracy: 1ns max
FFT Spectrum Analyzer Frequency Range: DC to 100 kHz SRS SR760
Amplitude Accuracy: ±0.2 dB
Distortion: < 75 dB below reference
RF Spectrum Analyzer Frequency Range: 1 kHz to 100 MHz Anritsu MS2601/ HP4195A
Amplitude: ±0.5 dB
Distortion and Spurious: < -70 dB
DC/AC Voltmeter 51/2 Digit DC accuracy Fluke 8840A
True RMS AC to 100 kHz
Thermal Converter Input Impedance: 50 Ω Ballantine 1395A-3
Input Voltage: 3 Vrms
Frequency: DC to 10 MHz
Accuracy: ±0.05dB
10 MHz Frequency Standard Frequency: 10 MHz ± .001 ppm SRS FS700
Phase Noise: < -130 dBc @ 100Hz
50 W Terminator 50 Ω ± 0.2 %, 1 Watt HP 11048C
ADJUSTMENTS
The following adjustments set the values of all of the variable components in
the DS335. After an adjustment has been made the associated calibrations
must be made. All adjustments must be complete before calibration is
started. First, remove the DS335's top cover by removing the four retaining
screws.) Set the "cal enable" jumper (JP200 switch 2) between pins 1 and 2.
NOTE: The chassis ground and circuit ground float relative to each other.
For voltage measurements use the FUNCTION output BNC shield as a
ground reference.
Output Amplifier Bandwidth
These adjustments correct the bandwidth of the output amplifier. A complete
calibration must be performed if these adjustments are changed. All of the
adjustments are on the bottom PCB. Use an insulated adjusting screwdriver.
1) Connect the output of the DS335 to the oscilloscope with a 50W
terminator. Set the DS335 to square wave, 8 Vpp, 100 Hz. Set the
scope to 2 V/div vertical and 5 ms/div horizontal. Adjust R703 for the
squarest output waveform.
2) Set the scope to 200ns/div. Adjust C707 for the fastest output risetime
without excessive overshoots.
3) Do a complete calibration of the DS335
DS335 Synthesized Function Generator