Anritsu MG3641A - Manual (Page 93)

SECTION 5 MEASUREMENT
SECTION 5
MEASUREMENT
5.1 Measurement of Sensitivity
The sensitivity of the receiver means the minimum signal input level required to output the rated signal of the receiver.
The following incidental conditions are required for the signal level, noise level, and signal distortion obtained in the
output side of the receiver:
• AM receiver ............. Indicated by the minimum value of the typically modulated carrier voltage required to output
the rated signal of the specified signal-noise rate (S/N). For example, when S/N = 20 dB, the
minimum value of the carrier input voltage for 60 % modulation required to output the 50-
mW signal is indicated by 10
µV.
• FM receiver .............. Indicated by the minimum value of the typically modulated carrier voltage required to obtain
the rated output and specified value (–12 dB in 400 MHz) of the signal to noise and distortion
(SINAD) obtained by adding the signal distortion to the signal-noise rate (S/N). In addition,
this sensitivity is indicated by the minimum value of the carrier voltage required to suppress
the receiver noise output by 20 dB at no-modulation. This is called a noise suppression (NQ)
sensitivity.
This section describes the latter 20 dB NQ sensitivity and explains how to measure the 12 dB SINAD sensitivity.