17. Pilot Second IF Amplifier Adjustments

Procedure 1. Position instrument on right side as shown in Figure 3-67, with bottom cover removed.

2.Set LINE switch to ON and press GNST PRESET) on HP 8568B (DUT), HP 8757A, and HP 8340A/B.

3.Connect 20 dB Attenuator and power splitter to RF OUTPUT of synthesized sweeper. Connect one arm of power splitter to R input of scalar network analyzer through detector as shown in Figure 3-67.

4.Set synthesized sweeper FREQUENCY MARKERS IN11) to 254 MHz and lM2) to 284 MHz.

5.Press Icw) 269 MHz on synthesized sweeper.

6.Connect Power Meter to the other power splitter port and set synthesized sweeper POWER LEVEL) for a Power Meter indication of -20.0 ho.2 dBm.

7.Disconnect Power Meter and connect power splitter output to A9J1, using adapter and BNC to SMB test cable.

8.Connect A9J2 to A input of scalar network analyzer through detector, using adapter and another BNC to SMB test cable.

9.Connect synthesized sweeper SWEEP OUTPUT (rear panel), Z-AXIS BLANK/MKRS (rear panel), and PULSE MODULATION INPUT (front panel) to proper rear-panel connectors on scalar network analyzer, shown in Figure 3-67.

10.On scalar network analyzer, turn channel 2 off and press m (A/R).

11.Set the scalar network analyzer [SCALE_) to 1 dB, and set (REF) (REF LEVEL) to + 10.00 dB. Set REF POSN (press REF POSN) to the fourth division from the bottom using the data knob.

12.On synthesized sweeper, press (W] (ON), [MKR SWEEP), and InF). Set SWEEP TIME to 500 ms.

13.Adjust REF LEVEL for a mid-screen response of signal on HP 8757A.

14.Adjust A9 269 MHz Bandpass Filter, A9C9, A9Cl0, A9Cl1, and A9C12, for best bandpass filter response with gain of greater than + 10 dB (above REF 1 line). See Figure 3-68 for location of adjustments. Figure 3-69 shows typical response when the bandpass filter is properly adjusted.

Adjustments 3-l 17