Implementation And Application Of Audio Modulation Signal Digital Of ZF-600A MW Transmitter

The implementation and application of audio modulation digitization of medium-wave broadcast transmitter (DX series transmitter) improved the reliability of the transmitter efficiently and reduced the cost of the transmitter. The most important point is that the efficiency has improved substantially. At the same time, the machine indicators have improved greatly. This is a technical revolution in broadcasting transmitters. It makes the medium-wave radio transmitter to develop to a direction of a large (large power), three tenors (high efficiency, high quality, high stability) and three states (solid state, digital, automatic), it has broad prospects for development.On the base of extensively reading the books and literature data about the design and application of MW transmitter modulation technique and A/D conversion technique, it analysize that the changes of the audio modulation signal being transmitted into the composite signal of audio and DC by audio management, and uses the A/D converter to sample, quantise and encode the composite signal, then transform it into digital signal of 12bit. Then it modulates and codes the digital signal of 12bit, the former eight, that are B1-B8, are applied to control the open-up and cutout of RF amplifier of 220 "big step" after encoded by modulation encoder; the latter four, that are B9-B12, are applied to control the open-up and cutout of RF amplifier of four "binary step" after coded by modulation encoder.Compared to the traditional analogue modulation transmitter, DX series transmitter replaces big-power wares,such as big-power audio amplifier, audio amplitude, audio frequency choke, and so on, with integrated mass, e.g. A/D converter, modulation coder.Thus it decreases cost, increase efficiency , and its sound quality is as good as that of the FW transmitter.Based on this, this paper mainly use A/D conversion technology to achieve the analog audio signal digital processing. We had a feasibility analysis on the realization and application of analog audio signal digital processing in medium-wave radio transmitter system, from which we have obtained the practical conclusion.This paper is subsidized by "western new engineering (xi-xin project)" and "1170 engineering (1170 project)" project funding of 802 station of Ji'An city of Jiang Xi province.