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The AMM-Audio Modulation Meter demodulates the 41.25 MHz I.F. carrier of a TV modulator so that the loudness of TV audio modulation can be measured. This meter measures the magnitude of audio loudness in RMS (dB), rather that in KHz of deviation. Peak deviation is not a reliable measure of perceived loudness, while the RMS content of program audio registers loudness much more accurately. The meter samples the highest audio level and holds it for measurement on the digital meter read-out so that 100% modulation level is indicated. In practice, the loudness, of several off-air stations are averaged and all other channels are set to the same loudness level. All tests are performed using the program audio actually on the channel. No test tones or other interruption of regular programming is needed to set audio levels accurately. The AMM also measures baseband audio levels on balanced or unbalanced audio facilities. The readings are true RMS and the measuring range indicates +20 to -60 dBm in a 600 ohm system. The meter input is high impedance so that the AMM can be bridged across the audio terminals without effecting the operating level. A phone jack is provided so that the operator can quality monitor the audio channel as well as measure the level. The AMM is battery operated and hand-held. Together with the VVM-Video Volt Meter, VMM-Video Modulation Meter, and the MMC-Modulation Measurement Center, this makes a complete modulation testing system for Cable Head-End TV modulators. This is the first coordinated TV modulator testing system. Nominal Deviation, +25 KHz = 0 dB Measurement, True RMS, with peak hold BASEBAND AUDIO INPUT Type, Balanced or Unbalanced Calibration, 0 dBm = .775 Vrms Measurement, True RMS, with peak hold AUDIO QUALITY MONITOR Type, Earphone Connector, Miniature phone jack (please look at our rules and privacy policy) |
L_Donaldson@modularparts.com (Liliana Donaldson) for more information. This email will be sent to Liliana Donaldson' actual email address.
