Belar: "When accuracy counts, count on Belar"


FMM-2 photo


The Belar Model FMM-2 FM Modulation Monitor is a precision wideband, all solid state FM monitor, designed to measure the total modulation characteristics of monaural as well as multiplexed FM transmitters. The Model FMM-2 is also used as a low distortion and low noise FM demodulator to drive the companion stereo and SCA monitors, as well as providing audio outputs for aural monitoring and proof of performance measurements.

The Model FMM-2 has set new standards in totally accurate measurement techniques. Utilizing such advanced design features as an ultra-linear digital discriminator, an almost distortionless and absolutely flat baseband signal is produced to ensure precise stereo and SCA decoding.

In addition to the normal FCC defined semi-peak metering, the FMM-2 incorporates a sample-hold peak modulation meter circuit, independent of modulation polarity, to allow the meter to respond accurately to program peaks.



Frequency Range			     88 to 108 mHz std.

                                        (fixed - specify carrier freq.)

RF Input 			     1 to 10 volts rms,

                                        50 ohms, BNC connector

Modulation Metering:

 Deviation Indication		     100% @ +/- 75 kHz, 0 to 133% range

 Accuracy			     +/-2% @ all modulation levels

 Characteristics		     selectable: peak (sample-hold)

                                        or semi-peak

Noise Measurement:

 FM Noise Range 		     - 50 dB to - 70 dB

 AM Noise Range 		     - 50 dB to - 70 dB

Test Function:

 Calibrate 			     Provides internal standard

                                         deviation reference

 Zero 				     Provides zero deviation for s/n

 RF Level 			     Calibrates AM noise function and

                                         carrier alarm reference level

 Carrier Alarm 			     Indicator adjusted for 90% carrier level


 Stereo Monitor 		     Wideband, 1.5v rms @ 1kohm unbalanced

 SCA Monitor 			     Wideband, 1.5v rms @ 1 kohm unbalanced

 Audio, (Program) 		     + 10 dBm, 600 ohms, balanced

 Audio, (Test) 			     5v rms, 10k ohms, unbalanced

Audio Output Specifications

 Frequency Response 		     +/- 0.01 dB

 Harmonic Distortion 		     0.01 % max

 Intermodulation Distortion 	     0.01% max (SMPTE)

 Signal-to-Noise Ratio 		     90 dB, min

Remote Outputs

 Carrier Level Alarm		     Provides "open collector" output,

                                         capable of sinking 20 ma @ 15 vdc

 Meter				     100% Peak Indicator, Adj. 

Peak Indicator 			     For interface to Model MP-8

                                         Remote Meter Panel (opt)

Dimensions 			     5.25"H x 10.5"D x 19"W (EIA Rack Mount)

Power Consumption 		     10 watts, 117 VAC std. 

                                         (234 VAC opt) 50/60 Hz

Shipping Weight  		     12 Ibs

© Copyright 2000 Belar Electronics Laboratory, Inc. All rights reserved. Specifications subject to change without prior notice.

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