11.Down/Up

Converter Adjustments

Reference

Related Performance Test

Description

IF-Display Section

A4A6 Down/Up Converter

Resolution Bandwidth Switching Uncertainty Test

The CAL OUTPUT signal is connected to the RF INPUT connector of the instrument and controls are set to display the signal in a narrow bandwidth. A marker is placed at the peak of the signal to measure the peak amplitude. The bandwidth is changed to a wide bandwidth and the Down/Up Converter is adjusted to place the peak amplitude of the signal the same as the level of the narrow bandwidth signal.

Optionally, the input signal is removed and the IF signal is monitored at the output of the Bandwidth Filters using a spectrum analyzer with an active probe. The 18.4 MHz Local Oscillator and all harmonics are then adjusted for minimum amplitude.

HP 85024A

HIGH FREOUENCY PROBE

PWER SUPPLY

Equipment

Procedure

Figure 3-50. Down/Up Converter Adjustments Setup

Spectrum Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 8566B Active Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 85024A

1.Position Instrument upright as shown in Figure 3-50 and remove top cover.2.Set LINE switch to ON and press (JNSTR PRESET].

3.Connect CAL OUTPUT to RF INPUT.

4.Key in [CENTER FREQUENCY) 20 MHz, (FREQUENCY SPAN) 10 kHz,

[ATTEN)P 0 dB, [REs) 1 kHz. ress LIN pushbutton, [PEAK SEARCH), and then MARKER a.

5.Key in IJREsBW) 1 MHz.

3-92 Adjustments