Belar FMCS–1L All-In-One FM Modulation Monitor – Lite



The Belar FMCS-1L provides a complete solution for the Analog portions of the FM signal. The unit combines the features and functions of an RF amplifier, FM demod, stereo demod, RDS decoder, SCA decoder, and FFT spectrum analyzer in one product.

Using state of the art DSP techniques all of FMCS-1L processing takes place in the digital domain, this results in FM analog performance that was previously not possible.

The Belar FMCS-1L All-in-One FM Modulation Monitor is a wideband FM monitor which meets the Federal Communications Commission requirements for measuring the total modulation characteristics of monaural as well as the stereo modulation characteristics of multiplexed FM transmitters. On board processing provides spectral analysis of the pre demodulation and post demodulation signals. Internally generated calibration signals permit checking monitor accuracy at any time. Ethernet/USB ports and a graphical user interface enable local or remote operation of the FMCS-1L via an external PC.


  • Frequency Agile Antenna and High Level RF Inputs
  • AM & Sync AM Noise Measurements
  • Variable Bandwidth Digital IF Filtering with HD Carrier Suppression
  • Digital FM Demodulation with 100 dB 75ms SNR
  • Variable BW Composite Filtering
  • Digital Stereo Demodulation with 90 dB L/R Separations
  • Full Metering of Analog Peak and RMS Values
  • RDS Injection and Data Decoding
  • Two Digital SCA Decoders
  • RF, Composite and Audio FFT Spectrum Analysis
  • RJ – 45 Ethernet Interface with Remote PC Software

Technical Specifications

RF Inputs

Frequency Range

  • 87.3 to 108.1 MHz, Frequency Agile
  • 100 kHz Increments

High Level Input

  • 400 mVrms to 3.5 Vrms , 50Ω, BNC Connector

Antenna Input

  • 100μV sensitivity, 75Ω, F-Type Connector
  • 500 mVrms Maximum



Modulation (Peak, Ave, Min)

  • Total, L, R, L+R, L-R
  • 0 to 150%, 0.1% resolution


  • 0 to 15.0%, 0.1% resolution



Total, L, R, L+R, LR

  • +3.0 to 120.0 dB, 0.1 dB resolution
  • Flat & 50μs or 75μs

AM Noise, Sync AM Noise

  • 0.0 to -100.0 dB, 0.1 dB resolution


  • 0.0 to 120.0 dB, 0.1 dB


  • 0.0 to 120.0 dB, 0.1 dB resolution



  • Total Peak Modulation
  • L+R Presence
  • RF Presence
  • Pilot Presence∙RDS Sync & Presence
  • SCA #1 Peak and Presence
  • SCA #2 Peak and Presence∙AM Noise Limit
  • SYNC AM Noise Limit


Alarm Outputs

Relays (4 assignable)

  • FORM C, 15-pin Female D-Sub Connector

 Computer Interface

  • USB Port
  • Ethernet 10/100 Base -TRJ-45 Jack




  • 19″x1.75″x14.5″ (48.26×4.45×36.83 cm),1 EIA Rack Unit

Power Requirements

  • 40 Watts, 90-264V, 47 to 63 Hz

Shipping Weight

  • 10 lbs (4.5 kg)

Shipping Carton

  • 22″x18″x6″ (55.9×45.7×15.2 cm)

Product Resources

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