Digital intercom system based on MPPSK (M-ary Phase Position Shift Keying) modulation

A digital walkie-talkie, modulation signal technology, applied in the field of digital walkie-talkie system, to achieve the effect of reliable demodulation

Inactive Publication Date: 2015-11-25
苏州东奇信息科技股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0029] Although the above-mentioned IIR-type digital impact filter has excellent demodulation performance, it also has many defects due to its unique and harsh composition conditions (see "Dual Carrier ABSK Communication System Based on the Same Narrowband Filter" for details, invention patent disclosure No.: CN102932298A")

Method used

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  • Digital intercom system based on MPPSK (M-ary Phase Position Shift Keying) modulation

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Embodiment Construction

[0094] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0095] Digital walkie-talkie transmitter system based on MPPSK modulation

[0096] The efficient modulation method used to replace the modulation method in the existing digital walkie-talkie system (such as the 4FSK modulation method of DMR digital walkie-talkie), that is, MPPSK modulation, is a key factor for a digital walkie-talkie based on MPPSK modulation. We hope it has the following three at the same time condition:

[0097] ① The sideband level is low.

[0098] It is required that the PSD sideband level of the digital walkie-talkie based on MPPSK modulation is at least 60dB lower than the carrier in the channel bandwidth of the left and right adjacent walkie-talkies, in order to reduce the interference of the MPPSK signal to other digital walkie-talkies of the adjacent frequency or the same frequency.

[0099] ②The symbol ra...

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Abstract

The invention discloses a digital intercom system based on MPPSK (M-ary Phase Position Shift Keying) modulation. The digital intercom system is characterized in that the MPPSK modulation is used as a modulation and demodulation manner of a physical layer of a digital intercom. According to special spectrum characteristics of an MPPSK modulated signal, high-speed intercom information is in plug-in transmission by utilizing the spectrum gap or the idle spectrum between adjacent channels in the existing digital intercom system. Normal communication of a receiving end of the system can be ensured only by completing adjacent-frequency or same-frequency interference elimination of the existing digital intercom on a digital base band. An MPPSK system is adopted in a transmitter and used as the modulation manner of the physical layer of the digital intercom; extra spectrum resources are not occupied; the high-speed intercom information is in plug-in transmission only by utilizing the spectrum gap or the idle spectrum between the adjacent channels in the existing digital intercom system; a receiver is only necessary to eliminate adjacent-frequency or same-frequency interference of other digital intercoms on the digital base band; and thus, normal demodulation of the MPPSK modulated signal can be ensured.

Description

technical field [0001] The invention relates to a digital communication system in the field of digital mobile communication, in particular to a digital walkie-talkie system based on MPPSK modulation. Background technique [0002] 1. Development Status of Digital Walkie-Talkie [0003] Walkie-talkie communication belongs to professional radio communication, which originated in the army, and is widely used in public security, fire protection, ambulance, petrochemical and civil construction and property management due to its unique advantages in cluster dispatching, emergency communication, instant communication, etc. , hotels, restaurants, shopping malls, schools and other fields play an important role in the national economy and daily life. [0004] In the past, walkie-talkies were all analog walkie-talkies. However, with the increase in the number of users, the spectrum resources are increasingly tight, and user needs are also diversifying. It is imperative to digitize the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04Q5/24
Inventor 张陈梅吴乐南但吉兵王继武
Owner 苏州东奇信息科技股份有限公司
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