120 MHz Low Pass Filter Check and Adjustment

Section V

TM 11-6625-2781-14&P-2

ADJUSTMENT PROCEDURES (cont' )

5-26. 120 MHz Low Pass Filter Check and Adjustment

REFERENCE: Service Sheet 3.

DESCRIPTION: 120 MHz low-pass filter pass band response may be checked using frequency response test 4-24. The

120 MHz low-pass filter is adjusted for flatness between 30 and 110 MHz using the HP 8443A Tracking

Generator/Counter as a leveled tracking source. By connecting the spectrum analyzer (P4) to the Tracking

Generator/Counter, the Tracking Generator frequency range is synchronized to the analyzer first local oscillator. (The

analyzer and the tracking generator track the same frequency range, allowing a swept view of the 120 MHz bandpass

shape.)

Figure 5-7. 120 MHz Low Pass Filter Adjustment Test Setup

EQUIPMENT:

Tracking Generator/Counter................................ ................................ ................................ ...................... HP 8443A

BNC Cable Assembly................................ ................................ ................................ .............................. HP 10503A

Extender Cable Assembly ................................ ................................ ................................ ............... HP 11592-60015

Nonmetallic Tuning Tool ................................ ................................ ................................ ..................... HP 8730-0013

Interconnecting Cable Assembly ................................ ................................ ................................ ..... HP 11592-60016

Cable Assembly ................................ ................................ ................................ .............................. HP 11592-60013

Interconnection Cable Assembly ................................ ................................ ................................ ..... HP 08443-60049

1. Connect the test setup in Figure 5-7 and make the following control settings:

ANALYZER:

RANGE MHz ................................ ................................ ................................ ................................ ................... 0-110

FREQUENCY ................................ ................................ ................................ ................................ ............... 80 MHz

FINE TUNE................................ ................................ ................................ ................................ ................ centered -

INPUT ATTENUATION................................ ................................ ................................ ................................ .... 10 dB

BANDWIDTH ................................ ................................ ................................ ................................ ............... 300 kHz

SCAN WIDTH ................................ ................................ ................................ ................................ ....PER DIVISION

SCAN WIDTH PER DIVISION ................................ ................................ ................................ ...................... 10 MHz

LOG/LINEAR ................................ ................................ ................................ ................................ ..................... LOG

5-14