For more than 30 years Belar has been making precision modulation monitoring products and established a reputation that makes their name synonymous with reliability.
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.
Main Features:
• Ultra-linear digital discriminator
• Digitally selectable peak indicator, adjustable in 1% increments from 1 to 199%, independent of modulation polarity
• Built-in voltmeter for AM and FM noise measurements
• Carrier alarm with front panel indicator
• Two wide-band outputs
• True peak or semi-peak metering
• Separate fixed 100% modulation indicator
• High visibility rear-illuminated meter
Specifications:
• 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
• 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
• Outputs:
• 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