Stanford Research Systems SR620, Руководство пользователя

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Performance Test 63
SR620 Universal Time Interval Counter
PERFORMANCE TESTS
These tests measure the performance of the
SR620 in comparison to its specifications.
Timebase Frequency
This test checks the frequency of the SR620's
10MHz clock. The clock should be recalibrated
whenever the frequency deviates significantly from
10MHz.
1) Allow the SR620 to warm up for at least 1/2
hour.
2) Set the SR620 mode to frequency, source to
A, arming to 1s gate, sample size to 1, A
trigger level to 0.00V, A termination to 50
Ohms.
3) Attach the frequency standard to the A input
and measure its frequency. Record the result.
Accuracy
This test checks that the SR620 will produce the
correct result given a known input. This test
does
not check the accuracy of the 10 MHz time base.
specification: 10 MHz ± .0035 Hz
1) Set the SR620 to Frequency Mode,A source,
1s gate, 1 sample.
2) Attach the rear panel 10MHz output to A,
terminate in 50 Ohms.
3) Verify that the reading is consistent with the
above specification. Record the reading.
Time Interval
This test tests the accuracy of time interval
measurements. The resolution is also checked.
specification: < ±1ns accuracy
< 50ps rms jitter
1) Set the pulse generator to square wave, 4V
amplitude, frequency to 10 kHz.
2) Tee the output of the pulse generator to the A
and B inputs of the SR620 using equal length
cables from the tee to the inputs.
3) Set the SR620 to time mode, source A, +TIME
arming, 1000 samples. Terminate the A and B
inputs in 50 ohms and set the trigger levels to
0.00V. Set both A and B slopes to +.
4) Display the mean and verify that the reading is
less than ±1ns. Record the reading.
5) Display the jitter and verify that the reading is
less than 50ps rms. Record the reading.
Trigger Sensitivity
These tests confirm that the A and B inputs and
UHF prescalers have normal sensitivity.
1) Attach the function generator's reference clock
input to the SR620's 10MHz output. Set the
function to square wave and the amplitude to
110mV pk-pk with no offset.
2) Connect the function generator to the SR620's
A input. Terminate the input into 50 ohms, set
the trigger slope to +, and set the trigger level
to 0.02 Volts (this centers the hysteresis about
0.00V).
3) Set the SR620's mode to Frequency, 1s gate,
1 sample, display to mean.
4) Set the source to A, the A trigger level to
0.02V, and measure the frequency at the
following frequencies: 0.1 Hz, 10Hz, 1kHz,
100kHz, 1MHz, and 10MHz. note: the 0.1 Hz
measurement will take at least 40s to stabilize.
The frequencies should read:
setting Frequency
Reading
0.1 Hz 0.1Hz ±20
µ
Hz
10 Hz 10 Hz ±1 mHz
1 kHz 1 kHz ±1 mHz
100 kHz 100 kHz ±0.01Hz
1 MHz 1 MHz ± 0.1 Hz
10 MHz 10 MHz ± 1.0 Hz
Record the results.
5) Set the source to B, the B trigger threshold to
0.02V, terminate the B input into 50 Ohms, set
the trigger slope to +, connect the function
generator to the SR620's B input, and
measure the same group of frequencies.
Record the results.
6) Attach the rf generator's reference input to the
SR620's 10MHz output.
7) Attach the generator's rf output to the SR620's
A input. Terminate the A input into 50 ohms.