Belar FMM-4A Automatic FM Frequency Monitor

BELAR FMM-4A AUTOMATIC FM FREQUENCY MONITOR

FMM-4A Photo

DESCRIPTION

The Belar FMM-4A is a highly accurate digital FM frequency monitor designed especially for automatic broadcast transmitter monitoring. The counter will accurately monitor FM Carrier, Pilot, and SCA Frequencies. A large 3½ digit LED display provides a range of ±19.99 kHz for Carrier, ±1999 Hz for SCA, and ±10 Hz for Pilot. Front panel LED indicators are provided to warn of low level input or loss of any monitoring frequencies. To prevent false alarms, the FMM-4A inhibits the off-frequency alarms until three successive errors are detected. Two levels of alarm are provided for Carrier deviations. An alarm is also provided to indicate an invalid count, which could result from too low an input level or a malfunction with the counter. An optional alarm relay board is available.

FEATURES

CARRIER

RF or LO and IF Inputs (when RFA-4 or RFA-1A is used)
±1 kHz Off-Frequency Alarm
±2 kHz Off-Frequency Alarm
Low-Level Alarm
FM Averaging Frequency Switch

PILOT *

±2 Hz Off-Frequency Alarm
Low-Level Alarm

SCA *

±500 Hz Off-Frequency Alarm
Low-Level Alarm

Invalid Count Alarm
Large 3½ digit LED display
Low profile design
Designed for ATS Operation

SPECIFICATIONS

Frequency Range                         see below

Display                                 Large 3½ digit LED

Gate Time                               2 seconds

Time Base                               6 MHz

Time Base Output                        6 MHz TTL compatible level

Invalid Count Alarm                     prevents false counts

                                           due to low level or problem in counter

Level Alarms                            3 LED Indicators



CARRIER

Frequency Range                         80 MHz to 120 MHz

Accuracy                                50 Hz (25 - 50 degrees C)

Sensitivity                             RF(LO/IF) - (200/100)mV

Resolution                              ±10 Hz

Range                                   ±19.99 kHz

Off-Frequency Alarms                    ±1 kHz & ±2 kHz



PILOT *

Frequency Range                         19 kHz ± 10 Hz

Accuracy                                0.01 Hz

Sensitivity                             500 mV

Resolution                              ±0.1 Hz

Range                                   ±10 Hz

Off-Frequency Alarms                    ±2 Hz



SCA *

Frequency Range                         67 kHz direct

                                        or follows range of Belar SCM-2 SCA monitor

Accuracy                                0.1 Hz

Sensitivity                             500 mV

Resolution                              ±1 Hz

Range                                   ±1999 Hz

Frequency Alarms                        ±500 Hz



Dimensions                              1.75"H x 12"D x 19"W

                                         (EIA Rack Mount)

Power Requirements                      115/230 VAC, 50/60 Hz

* If the BELAR FMS-2 or FMSA-1 is not used for obtaining a pure pilot and/or the BELAR SCM-2 is not used for obtaining a pure subcarrier, a filtered source for pilot and/or 67 KHz subcarrier is required.