Multimode half-duplex frequency modulation transceiver

A transceiver, half-duplex technology, applied in the field of communication, can solve the problems of unfavorable miniaturization, complexity, cost and volume increase, and achieve the effect of improving adaptability

Inactive Publication Date: 2010-11-24
周运伟
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

However, a typical triode frequency modulation circuit is used to adapt to 3 or 4 carrier channel bandwidths in 25KHz, 20KHz, 12.5KHz and 6.25KHz and 3 or 4 frequency modulation methods in linear FM, FFSK, C4FM, 4FSK There is often a sharp contradiction between modulation accuracy, linearity and frequency stability; if the number of similar frequency modulation circuits is increased, it will increase complexity, cost and volume, which is not conducive to miniaturization

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  • Multimode half-duplex frequency modulation transceiver

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Embodiment Construction

[0020] A multi-mode half-duplex FM transceiver such as figure 2 shown. In this design scheme, 201 is the main clock, 202 is the direct digital synthesis carrier generation circuit, 203 is the low-pass filter, 204 is the frequency multiplier, and they form a complete carrier generation circuit; adopting this composition scheme is mainly to make The spurs of the carrier generated in the form of direct digital synthesis (DDS) can meet the application requirements, and at the same time, a DDS chip that can keep the carrier phase continuous when switching between different frequencies is used; the frequency multiplier is used, on the one hand, it can reduce the direct digital synthesis ( The frequency range covered by the carrier generated in the form of DDS (to facilitate the control of spurious levels), on the other hand, is to reduce the number of up / down conversion stages and improve the suppression of unused sideband components in the up / down conversion process; For example,...

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Abstract

The invention relates to a multimode half-duplex frequency modulation transceiver, which belongs to the field of communication. The multimode half-duplex frequency modulation transceiver generates a modulated carrier wave which is required during transmission and a local carrier wave which is required by final stage down frequency conversion during receiving by adopting a carrier wave generating circuit in a direct digital synthesis form, so the contradiction between the modulation accuracy and the linearity, and frequency stability and the frequency accuracy in the design of the multimode half-duplex frequency modulation transceiver is effectively solved. The multimode half-duplex frequency modulation transceiver can compatibly realize a frequency modulation (FM) modulation mode of a narrow band in an analog-and-digital form and can compatibly realize an FM / Chirp modulation mode adopting a step Chirp pulse carrier wave in the analog-and-digital form, so that the adaptability of the multimode half-duplex frequency modulation transceiver is further improved.

Description

technical field [0001] The invention relates to a multi-mode half-duplex frequency modulation transceiver, which belongs to the communication field. Background technique [0002] Typical representatives of half-duplex FM transceivers are handheld, vehicle-mounted and backpack-mounted FM walkie-talkies. The FM modulation types used are mainly narrow-band analog linear FM and digital FM modulation. Among them, digital FM modulation The main methods are 2FSK, FFSK, 4FSK, C4FM, etc., and the commonly used carrier channel bandwidth types are 25KHz, 20KHz, 12.5KHz and 6.25KHz. [0003] At present, most walkie-talkies using narrowband FM modulation are designed to be compatible with analog linear FM modulation and digital FM modulation (such as FFSK, 4FSK) and support multiple operating modes (referred to as multi-mode) with different carrier channel bandwidths, so as to adapt to different application needs. When different carrier channel bandwidths are used, it means that the mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/40H04B1/707H04L5/16
CPCH04B1/69H04B2001/6912H04L27/10
Inventor 周运伟
Owner 周运伟
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