Amplifier current of digital am MW broadcast transmitter is an important technical parameters, its quantitative "data memory" directly reflects the State of operation of the transmitter. Digital am radio transmitter combines digital modulation and digital processing together; audio signal a/d inputs, MD conversion processing 12bit digital signal, encoded by the modulation and coding of digital outputs to control the opening and closing of the RF power amplifier module. Based on how much open PA power amplifier block number, for transmitter RF output level control, power combination, band-pass filter to remove quantization step without harmonics. Finally got RF modulated signal.3R4service manual download site
3R4service manual download site
PA power amplifier module in working at fast switching status at any time. Low power consumption and high efficiency. RF PA power amplifier, digital modulation signals, DC voltage, high voltage, such as the junction, the outgoing network interface. If the PA amplifier current is too high. Light burning fuse, penetrated PA power amplifier PA. field effect tube amplifiers. Synthesis of the steps could lead to the damage.3R4service manual download site
3R4service manual download site
PA power amplifier of high currents caused by a variety of reasons, the transmitter does not match the output impedance of antenna tuning network and network error, transmitter modulation amplitude too large. For such reasons as improper use.3R4service manual download site
3R4service manual download site
1. first determine if transmitter does not match the output impedance of antenna tuning network and network errors caused.3R4service manual download site
3R4service manual download site
The modulated coded recycle part of the use of the most advanced digital modulation and coding techniques. Carrier opened at a time when 18 PA power amplifier. RF power is 10kW, amplifier output current of 50A. 42 PA power amplifier order cycle modulation and coding.3R4service manual download site
3R4service manual download site
First turn off modulation and coding in a shutdown state digital signal, the controller board (ILA/HG3.624.009PL) plug on the switch s docking to the OFF state. Not allowing modulated digital signal into the PA power amplifier. In opened l to 18th when the RF power amplifier, immediately closed digital loop modulation and coding signals. Turn the digital modulation and coding (ILA/HG2.871.010DL) s for switch on OFF status. Has been opened 18 PA power plates, cut off the audio signal input, smart incident adjustments on the display to 10kW. Amplifier current normal values should be 50A. If too high or too low, the transmitter does not match the output impedance of antenna tuning network and network.

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