The Belar AMMA-2 is a microprocessor-based digital AM modulation monitor/analyser that accurately measures positive and negative peak modulation, peaks per minute, average peak modulation, modulation density, etc.
In addition to monitoring standard AM modulation, the AMMA-2 accurately monitors modulation dependent carrier level (MDCL) AM transmissions. During MDCL transmissions, the RF carrier level becomes a dynamic component of the AM signal. The AMMA-2 tracks the carrier, capturing the highest and lowest values of the carrier level, as well as the high/low carrier decibel ratio. The modulation readings are referenced to the appropriate carrier level for the MDCL system in use. The optional remote meter panel displays positive modulation, negative modulation and carrier level simultaneously on three large analogue meters.
The AMMA-2 features user-defined parameters and settings for maximum flexibility. Two large UP/DOWN menu keys are used to scroll the 16-character alphanumeric display to the desired menu; the UP/DOWN parameter keys are then used to select the desired setting. The unit’s configuration can be saved to the built-in non-volatile memory so that settings are retained in the event of power loss.
A noise menu selection displays on the front panel the detected SNR in rms in decibels (flat or unemphasised).
A Carrier Cutoff indicator consisting of three front panel LEDs continuously monitors the negative modulation approach to carrier cutoff.
A unique “Normal Modulation” indicator shows when the modulation is within user-defined parameters.
A built-in audio failure alarm alerts you to loss of modulation or drops in modulation level.
An RS-232/RS-422 port allows the AMMA-2 to be accessed via a personal computer. The ASCII command set, documented in the user manual, provides an easy way for users to write their own command and control software. Alternatively, the AMMA-2 will be supported in the future by Wizard software, which provides unit control and logging and graphing capability for all AMMA-2 measurements.
A remote alarm connector consisting of 8 pairs of relay contacts provides alarm status information for hardwired applications. Deactivation of the NRSC can be selected internally by moving a jumper connector.