MODULATORS FOR TV-TRANSMITTERS read more PDF Modulators are intended for carrier frequency formation and TV-signal frequency translation (image and sound) to necessary TV- channel frequency. Modulators are used in TV-transmitters, cable TV systems, MMDS and other systems of TV-signal transmitting. Carries out: - stabilization of sound and image carrier frequencies by the synthesizers based on the thermos-tatted frequency oscillator;
- forming of signal with single side band by the SAW filter;
- stabilization of output signal level;
- indication of video signal absent;
- indication of over modulation of audio signal;
- high amplitude and frequency linearity of the section;
- correction of amplitude non- linearity of power amplifier of the TV-transmitters;
- balanced input for audio signal.
SPECIFICATIONS | | Image | Sound | | Frequency range | 20...6C106 Hz | 20...14C103 Hz | | Modulation type | amplitude | frequency | Nominal level of input signal | 1V(at Rinp=75 Ohms) | 0,75V(at Rinp=600 Ohms) | | Input signal levels range | 0,5...1,5 V | 0,25...1,75 V | | Signal/noise ratio | 60 dB | 60 dB | | Amplitude frequency characteristics unevenness of video signal | ±0,2 dB | |
| Output signal to channel intermodulation products ratio | 60 dB | | Non-linearity of carrier frequency: | | -in VHF range | ± 50 Hz | | -in UHFrange | ± 200 Hz | | Power supply | (220± 20) V | | Operating temperature range | 5...450С | | HF signal output level at Rloading=50/75 Ohms | 0,3...3 V |
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