Stanford Research Systems DS335, User Manual

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Performance Tests 4-11
DS335 Synthesized Function Generator
HARMONIC DISTORTION This test measures the DS335's sine wave harmonic distortion.
specification:
≤
-60 dBc, frequency
≤
100 kHz
≤
-50 dBc, frequency 0.1 to 1 MHz
≤
-40 dBc, frequency 1 to 3.1 MHz
1) Connect the DS335 output to the FFT analyzer input with a 50W
terminator. Set the DS335 to sine wave, 100Hz, 1 Vpp, and 50
Ω
Load
Impedance.
2) Adjust the FFT analyzer to view the fundamental and its harmonics.
Verify that all harmonics are below -60 dBc.
3) Repeat step 2 at 1 kHz and 10 kHz.
4) Connect the DS335 output to the RF spectrum analyzer input. Set the
DS335 to 50 kHz. Verify that the harmonics are at least -60 dBc.
5) Set the DS335 to 500 kHz, and 3 MHz, and verify that all harmonics are
at least -50 dBc, and -40 dBc, respectively. Record the results.
PHASE NOISE This test measures the integrated phase noise of the DS335's output in a 15
kHz band about carrier. This test is performed at 1 MHz to minimize the
contribution of discrete spurs to the measurement.
specification: < -60 dBc in a 30 kHz band centered about the carrier,
exclusive of discrete spurious signals.
1) Set the DS335 to sine wave, 10.001 MHz, 1Vrms.
2) Record the Phase noise reading from the FFT screen.
SQUARE WAVE RISE TIME This test measures the rise time and aberrations of the square wave output.
specification: rise time < 20 ns
overshoot < 2% of peak-to-peak output
1) Connect the output of the DS335 to the 350 MHz oscilloscope with a
50W terminator. Set the DS335 to square wave, 1 MHz, 10 Vpp, and
50
Ω
Load Impedance.
2) Set the oscilloscope to 2 V/div vertical and 5 ns/div horizontal. Measure
the time between the 10% and 90% points and verify that it is less than
20ns. Record the results.
3) Set the oscilloscope to 1 V/div vertical and 100 ns/div horizontal. Verify
that the overshoots and undershoots are less than ± 200 mV. Record
the results.
SQUARE WAVE SYMMETRY This test measures the symmetry of the square wave output.
specification: < 1% of 3ns
1) Connect the output of the DS335 to the A input of the time interval
counter and terminate into 50W. Set the DS335 to square wave, 1 MHz,
5 Vpp, and 50
Ω
Load Impedance.