BRUEL & KJAER 2006 - Page 8

"split" so that it is fed both to a Foster-Seeley type FM-detector, and to the
third IF -stage for further amplification after which it is applied to a con-
ventional AM-detector and peak indicating RF-meter.
The demodulated signal is then selected for further amplification in a low
frequency amplifier. Finally the signal is fed to a rectifier for meter detec-
tion, or to a loudspeaker for aural detection. The absolute sensitivity of the
Heterodyne Voltmeter Type 2006 can be checked by means of a built-in
reference oscillator which supplies a highly stabilized voltage to the terminal
marked REF. VOLTAGE on the front plate. Possible sensitivity adjustment
4G54 . i4
Fig. 1.4. FM-Discriminator and IF-Frequency Response (Wide) Characteristics
Oscilloscope setting:
x:
130 kHz/em.
y: Di.'lcriminator curve: 100 mV/cm.
IF-Frequency Response: 10 mV/cm.
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