Stanford Research Systems DS335, User Manual

Page: 56 / 86

4-10 Performance Tests
DS335 Synthesized Function Generator
2) Set the DS335 to 5V offset. Read the voltmeter and record the result.
The result should be b4.94V and +5.06V.
3) Set the DS335 to -5V offset. Read the voltmeter and record the result.
The result should be between -5.06V and -4.940V.
4) Set the DS335 to 0V offset. Read the voltmeter and record the result.
The result should be between -0.2 mV and +0.2mV.
DC+AC
specification: < ±80mV at full output
1) Connect the DS335's output to the voltmeter with a 50W terminator. Set
the DS335 to sine wave, 1 kHz, 10Vpp, 0V offset, and 50
Ω
Load
Impedance. Set the voltmeter to measure DC voltage.
2) Measure the offset voltage and verify that it is between -80mV and
+80mV. Record the result.
3) Repeat step 2 at 100kHz, 1MHz, and 3.1MHz. Record the results and
verify that the offset is between -80mV and +80mV at all of the
frequencies.
SUBHARMONICS This test measures the subharmonic content of the DS335's sinewave
output. The frequencies in this test are picked such that spurious
frequencies from the DDS process do not fall on the carrier position.
specification: <-70 dBc
1) Connect the DS335 to the RF spectrum analyzer. Set the DS335 to sine
wave,(10Vpp), 0V offset, and 50
Ω
Load Impedance.
2) Set the DS335 to 102 kHz. Set the spectrum analyzer to 51 kHz center
frequency, 10 kHz span. The carrier amplitude at 51 kHz should be less
than -70 dBc. Record the result.
3) Set the DS335 to 1.002 MHz, and the spectrum analyzer to 501 kHz.
Measure and record the amplitude of the 501 kHz carrier. It should be
less that -70 dBc. Repeat for 3.1MHz.
SPURIOUS SIGNALS These tests measure the spurious signals on the DS335's sine wave outputs.
They check both close-in and wide band spurs.
specification:
≤
-65 dBc to 1MHz
≤
-55 dBc to 3.1MHz
1) Connect the DS335 to the RF spectrum analyzer. Set the DS335 to sine
wave,1Vpp, 0V offset , and 50
Ω
Load Impedance.
2) Set the DS335 to 100 kHz. Set the spectrum analyzer to 100 kHz center
frequency, 100 kHz span. Measure the amplitude of the spurious signals
and verify that they are
≤
-65 dBc. Increase the span and check again.
3) Set the DS335 to 2 MHz. Set the spectrum analyzer to 2 MHz center
frequency, 100 kHz span. Measure the amplitude of the spurious signals
and verify that they are
≤
-55 dBc. Increase the span and check again.