Digital DPMR (digital private mobile radio) interphone based on single-point modulation of digital frequency synthesizer

Abstract

The invention relates to the technical field of wireless communication, provides a digital DPMR (digital private mobile radio) interphone based on single-point modulation of a digital frequency synthesizer, which is high in integration level, short in phase lock time, free from debugging, simple in circuit and high in product anti-jamming property, and can achieve fast and batched production. The digital DPMR interphone comprises a transmission circuit and a receiving circuit, wherein the transmission circuit comprises a transmission channel module, the digital frequency synthesizer, an MCU (microprogrammed control unit) controller, a base band processor and a microphone, which are sequentially connected, the base band processor is connected with a vocoder and TCXO=Temperature Compensated Crystal Oscillator respectively, and a voltage controlled crystal oscillator is connected between the base band processor and the digital frequency synthesizer; and the receiving circuit comprises a receiving channel module, a frequency detector, a low pass filter, an infra-acoustic frequency, the MCU controller, an audio power amplifier and a loudspeaker, which are sequentially connected, and the base band processor is also sequentially connected with the digital frequency synthesizer and the receiving channel module through the voltage controlled crystal oscillator.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a digital DPMR walkie-talkie based on single-point modulation of a digital frequency synthesizer. Background technique [0002] With the development of radio communication technology, people have higher requirements for the quality of wireless communication, but radio spectrum resources are increasingly scarce. The emergence of digital walkie-talkies provides more abundant, open and powerful types of use and user needs. As we all know , DPMR is a digital walkie-talkie standard published by ETSI. Applications suitable for commercial, professional, and public safety users; standards such as NXDN and DCR have been formulated in succession. DPMR adopts FDMA technology to provide low-cost digital voice and data solutions. DPMR effectively reduces channel spacing and improves spectrum utilization efficiency by adopting 6.25KHz FDMA technology and 4FSK modulation technol...

AI Technical Summary

Problems solved by technology

Therefore, it is possible to transmit with reduced power, thereby saving battery life and extending the use time of wireless devices, but because the traditional FDMA baseband circuit principle is the same as that of the traditional baseband circuit, they are all composed of a phase-locked loop And the voltage-controlled crystal oscillator (VCO) to generate the transmitted baseband carrier signal or the first local oscillator signal received, the existing circuit is complex, debugging is difficult, the consistency of components is high, and it is difficult to quickly mass-produce

Cause high cost of the whole machine

The locking time of the phase-locked loop is relatively long

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