19.Second Converter Adjustments

48.Disconnect cable connected to A23A3J2 and connect to A23A3Jl (1ST IF IN). Reconnect semi-rigid cable to A23A3J2 that was disconnected in step 36.

49.Set the synthesized sweeper’s a for 2052.5 MHz ho.1 MHz. Adjust a to center the bandpass signal.

50.Adjust A23A3 Zl, 22, 23, and L2 for best bandpass shape and flatness at maximum amplitude of signal displayed on Scalar network analyzer. A typical properly-adjusted bandpass filter response is shown in Figure 3-76 and Figure 3-77. See Figure 3-73 for location of adjustments. The bandpass response should be 222 MHz.

1i i i i ii i I

Figure 3-76. Typical Bandpass (SHIFT T)Figure 3-77. Typical Bandpass (SHIFT 1)

51.Keyin=@) u and note amplitude of the bandpass signal peak. Key in (SHIFT) a T and note amplitude of the bandpass signal peak.

52.Continue to key in ISHIFT) @j u then m a T while adjusting A23A3Z4 for maximum amplitude and the same amplitude in both states of the Second LO fcO.1 dB.

3-128 Adjustments