Channel C Sensitivity Check - Keithley 776 Instruction Manual

Figure 5-3. Channels A and B Sensitivity Test Set-up.
SIGNAL GENERATOR
1. Connect the test equipment as described in Figure 5-3.
2. Press Model 776 push-buttons in the following
sequence [2nd] , [DCL] and then [50 Ω ] .
3. Set Synthesizer frequency and amplitude as given in
the following table and verify a stable counter readings as
follows:
SYNTH SIGNAL REQUIRED
FREQ LEVEL READING
1 MHz 50 mV 1.000000000 E+6
80 MHz 50 mV
100 MHz 50 mV 100.0000000 E+6
150 MHz 50 mV
225 MHz 50 mV
4. Change synthesizer frequency setting to 10 MHz and
signal level setting to 50 mV rms.
5. Press [LPF] push-button and observe that the counter
does not process any more readings.
6. Again press [LPF] and then [x10] push-button and
observe that the Model 776 still does not process readings.
7. Change synthesizer amplitude level setting to 250 mV
rms.
8. Verify that counter reading is 10 MHz ±20 MHz.
9. Modify the connections in Figure 5-5 above so that
the synthesizer will now be connected to Channel B.
Select [FREQ B] .
10. Repeat the procedure above to verify Channel B sen-
sitivity.
REF
IN
RF
OUT
ALLOWED
ERROR
±2 MHz
80.0000000 E+6 ±0.2 Hz
±0.2 Hz
150.000000 E+6 ±2 Hz
225.000000 E+6 ±2 Hz
REAR PANEL CONNECTIONS

5-10-2. Channel C Sensitivity Check

Equipment: Synthesized signal generator
Procedure:
1. Connect the test equipment as described in Figure 5-4.
2. Press Model 776 push-buttons in the following
sequence: [2nd] , [DCL] and then [FREQ C] .
3. Set Synthesizer frequency and amplitude as given in
the following table and verify a stable counter readings as
follows:
SYNTH SIGNAL
FREQ LEVEL
50 MHz 15 mV
100 MHz 15 mV
500 MHz 15 mV
1000 MHz 15 mV
2000 MHz 15 mV
2400 MHz 15 mV
5-10-3. Period A, Period A Averaged
Operation Check
Equipment: Synthesized signal generator
Procedure:
1. Connect the test equipment as described in Figure 5-5.
2. Press Model 776 push-buttons in the following
sequence: [2nd] , [DCL] , [PER A] and then [50 Ω ] .
Maintenance and Performance Tests
UUT
MODEL 776 10MHz
COUNTER/TIMER OUT
C
A
COUNTER ALLOWED
READING ERROR
50.0000000 E+6 ±1 LSD
100.0000000 E+6 ±2 LSD
500.000000 E+6 ±1 LSD
1.000000000 E+9 ±2 LSD
2.00000000 E+9 ±1 LSD
2.40000000 E+9 ±1 LSD
B
5-5