Double-frequency vehicle-mounted interphone

Abstract

The invention discloses a double-frequency vehicle-mounted interphone with low cost and high performance. The double-frequency vehicle-mounted interphone adopts a single radio frequency power amplifier tube for realizing two high-performance broadband UHF and VHF radio frequency power amplifier circuits, and the technical difficulty that antenna port radio frequency output out-of-band rejection capability is poor when a double-frequency vehicle-mounted interphone adopts a single radio frequency power amplifier is solved by adding an isolation control circuit. Besides, an RDA1846S radio frequency single chip is taken as a UHF and VHF main radio frequency chip for a solution of the double-frequency vehicle-mounted interphone, and a UHF frequency selecting and amplifying circuit and a VHF frequency selecting and amplifying circuit adopt amplifying circuits with varator tuning frequency selecting function, an out-of-band interference signal can be filtered out and inhibited, and receivingand anti-interference capabilities of the RDA1846S radio frequency chip are improved. The double-frequency vehicle-mounted interphone disclosed by the invention has simple circuit, low cost and excellent in performance, and is easy to produce.

Description

technical field [0001] The invention relates to the technical field of vehicle-mounted walkie-talkies, in particular to a dual-frequency vehicle-mounted walkie-talkie. Background technique [0002] The dual-frequency vehicle-mounted walkie-talkie has the characteristics of long communication distance, strong adaptability, and flexible application. It is widely used in various occasions such as transportation, social service industry, disaster relief, forest fire prevention, and emergency communication. The traditional solution uses two completely independent discrete components for design, and uses dual radio frequency power amplifier tubes to complete the transmission of UHF and VHF frequency bands, dual independent UHF and VHF voltage-controlled oscillators, phase-locked circuits and receiving circuits, etc. The system is complex , High cost, cumbersome debugging, difficult to control consistency, low production pass-through rate, so there is an urgent need for a low-cost,...

AI Technical Summary

Problems solved by technology

[0004] RDA1846S RF chip, because the receiver amplifier adopts 130-520MHZ or wider frequency amplifier, it has no ability to suppress the received out-of-band signal, resulting in poor anti-interference ability for reception

When applied to a handheld walkie-talkie, the performance is not obvious due to the low antenna gain

When used in a vehicle-mounted walkie-talkie, the antenna gain is high, and the problem of poor anti-interference ability is obvious, resulting in poor communication effect and distance

[0005] Due to the above reasons, the dual-frequency vehicle-mounted walkie-talkie adopts two independent traditional discrete component designs, and the market price is high, which limits the wide application of dual-frequency vehicle-mounted walkie-talkies in various fields.

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