TM 11-6625-2781-14&P-2
Section IV
PERFORMANCE TEST PROCEDURES
4-22. PERFORMANCE TEST PROCEDURES
4-23. Input Impedance
SPECIFICATION:
Input Impedance: 50-ohm nominal. Reflection Coefficient ≤ .13 (1.3 SWR) for input attenuator settings ≤ 0dB.
0
1
DESCRIPTION:
The RF input impedance is checked in two steps over the frequency range of 2 kHz to 110 MHz. A vector impedance
meter is used to check the 500 kHz to 110 MHz range. Over the 2 kHz to 500 kHz range, an oscillator is terminated in a
known impedance and calibrated. The voltage across the know impedance is then compared with the voltage across the
analyzer input.
Figure 4-3. Input Impedance Accuracy Test: 500 kHz to 110 MHz
EQUIPMENT:
RF Impedance Meter ................................ ................................ ................................ .......................... HP 4815A
Test Oscillator ................................ ................................ ................................ ................................ ...... HP 651B
AC Voltmeter ................................ ................................ ................................ ................................ ........ HP 400E
50-ohm Termination ................................ ................................ ................................ ......................... HP 11593A
BNC Cable Assembly (2) ................................ ................................ ................................ .................. HP 10503A
BNC Tee ................................ ................................ ................................ ................................ ............. UG-274B/
1
Connect equipment as shown in Figure 4-3 and make the following control settings:
ANALYZER:
RANGE MHz ................................ ................................ ................................ ................................ ............... 0-11
FREQUENCY ................................ ................................ ................................ ................................ ......... 30 MHz
4-6
