Agilent Technologies 2948, 2712A manual Fl Channel Config, Period

Model 8904A Service

3b. Clock Checks (Using a Counter)

a.If the counter has an external 10 MHz timebase reference input, connect it to the rear-panel 10 MHz REF OUT of the Multifunction Synthesizer.

NOTE

If the counter does not have an external reference, the readings in the following steps may be off several counts. This does not indicate a failure.

b.Connect the high-impedance counter input to pin 3 of U2. The counter should read within one count of 6.71088 MHz.

c.Connect the counter to pin 2 of U2. The counter should read within one count of 1.67772 MHz.

4a. Digital-to-AnalogConverter Check (Using an Oscilloscope)

a. On the Multifunction Synthesizer, press SHIFT PRESET. After the instrument presets, key in

For A3 Output Assembly For A10 Output Assembly

fl (Channel Config.)	fl (Channel Config.)
NEXT	NEXT NEXT
WAVE FORM (t	WAVE FORM (t
FREQ 25.6 Hz	FREQ 25.6 Hz
AMPTD 10 V	AMPTD 10 V

NOTE

Setting the frequency to exactly 25.6 Hz inputs a TTL squarewave to each input of the DAC latches. As the DAC’s data input lines are probed from the most significant bit the the least significant bit, the frequency is consecutively divided by two.

b.Connect a dc coupled, high-impedance oscilloscope to the pin of the IC listed below. The waveform should be a TTL squarewave with an approximate period as indicated in the table.

IC on A3 or A10	Pin	Period
u5	14	19.1 ps
u5	13	38.1 ps
u5	11	76.3 ps
u5	6	153 ps
u5	4	305 ps
u5	3	610 ps
u4	14	1.22 ms
u4	13	2.44 ms
u4	11	4.88 ms
u4	6	9.8 ms
u4	4	19.5 ms
u4	3	39.1 ms

Troubleshooting (Digital/Output Interface) 8-33