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Digital interphone with digital and analogue hybrid receiving function

A hybrid technology of digital walkie-talkie and analog, which is applied in the direction of the two-way line system station to achieve the effect of solving frequency congestion and improving spectrum utilization

Inactive Publication Date: 2012-07-11
天津七一二移动通信有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] At present, the design schemes of different manufacturers have different technical characteristics, and the effects obtained by different design schemes are also different. At present, the digital walkie-talkie market does not support 51 CTCSS codes, and the number and frequency offset of CTCSS / CDCSS frequency offset can be set independently. Digital walkie-talkies with analog mixed reception functions appear, and there is no report of such technology in the literature

Method used

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  • Digital interphone with digital and analogue hybrid receiving function

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Embodiment Construction

[0030] Embodiments of the present invention are described in detail below in conjunction with the accompanying drawings:

[0031] CTCSS (Continuous Tone Controlled Squelch System), continuous voice control squelch system, commonly known as sub-audio, is a technology that transmits frequencies lower than the audio frequency (67Hz-250.3Hz) in the audio signal. Because its frequency range is below the standard audio frequency, it is called sub-audio frequency.

[0032] There is also a digital sub-audio, the English name of digital sub-audio (Coutinus Digital Controlled Squelech System) and its Chinese meaning is continuous digital coded squelch system, referred to as CDCSS. The function of digital sub-audio is the same as that of sub-audio, the difference is that it is transmitted together with the audio signal in digital encoding. Both CTCSS and CDCSS belong to the international common signaling standard. The frequency range of CTCSS is from 67.0Hz to 250.3Hz. There are 38 sta...

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Abstract

The invention relates to a digital interphone with a digital and analogue hybrid receiving function. A receiving circuit consists of a voice coding and decoding chip and a digital interphone baseband signal processing chip SCT3252, identifies a digital call and an analogue call by using a continuous tone controlled squelch system (CTCSS) / continuous digital controlled squelch system (CDCSS) technology, performs analogue demodulation on a code within the first 20ms in a decoding stage, extracts a CTCSS code from the code, performs digital demodulation on the code, is shifted into a digital receiving state if not extracting the CTCSS code, and is shifted into an analogue receiving state if extracting the CTCSS code which is consistent with a CTCSS code set by the digital interphone, so that digital and analogue hybrid receiving is realized. The spectral efficiency is improved; and the digital interphone is a solution for frequency congestion, and has far-reaching significance.

Description

technical field [0001] The invention relates to a digital walkie-talkie, in particular to a digital walkie-talkie with mixed receiving functions of digital and analog. Background technique [0002] The analog walkie-talkie modulates the stored signal onto the transmit frequency of the walkie-talkie. A digital walkie-talkie is a walkie-talkie designed with digital technology. The digital walkie-talkie digitizes the voice signal and transmits it in the form of digital code, that is to say, all the modulations on the transmission frequency of the walkie-talkie are digital. [0003] Digital walkie-talkies have many advantages. For example, more users can be loaded on a designated channel, such as 25KHz, and spectrum utilization can be improved. This is a solution to frequency congestion and has long-term significance. Analog walkie-talkies appeared earlier than digital walkie-talkies. Mature technology and price advantages make digital walkie-talkies unable to completely repla...

Claims

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Application Information

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IPC IPC(8): H04Q5/24
Inventor 张财元黄振华李辉辉张键王伟刘武超康保亮
Owner 天津七一二移动通信有限公司
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