In-band common frequency digital code cordless telephone

Abstract

The in-band digital wireless telephone is formed from two portions of mother machine and submachine. Its circuit portion is formed from control circuit, digital signal processing circuit, radio-frequency receiving and transmitting circuit, speech receiving and transmitting circuit, storage circuit, display circuit, keyboard input circuit, A / D converter circuit, interface circuit and power supply circuit which are mutually electrically connected together. Said invention integrates the modern digital signal processing techniques of speech coding, channel coding, digital modulation and demodulation and digital channel equalization into one body, and adopts monolithic integrated circuit chip to implement said invention, so that it can obtain high session quality, etc.

Description

(1) Technical field [0001] The invention relates to the technical field of communication, signal processing and software radio, in particular to an in-band co-frequency digital cordless telephone. (2) Background technology [0002] At present, my country's cordless phones are still dominated by analog cordless phones. There are many deficiencies in analog telephones: first, analog cordless telephones transmit analog signals, the signal processing method is simple, the power consumption is relatively large, and the influence of interference and noise cannot be effectively eliminated, resulting in unsatisfactory call quality in many cases; Second, the frequency utilization rate of analog cordless phones is not high, and the channel capacity is low. The cordless phone standard formulated in my country in 1994 is 20 pairs of frequencies of 45 / 48MHz, and the frequency bandwidth occupied by each channel is 25kHz; The analog cordless phone uses analog modulation transmission, which ...

AI Technical Summary

Problems solved by technology

There are many deficiencies in analog telephones: first, analog cordless telephones transmit analog signals, the signal processing method is simple, the power consumption is relatively large, and the influence of interference and noise cannot be effectively eliminated, resulting in unsatisfactory call quality in many cases; Second, the frequency utilization rate of analog cordless phones is not high, and the channel capacity is low. The cordless phone standard formulated in my country in 1994 is 20 pairs of frequencies of 45 / 48MHz, and the frequency bandwidth occupied by each channel is 25kHz; The analog cordless phone uses analog modulation transmission, which is easy to be illegally tapped and eavesdropped, and the security cannot be fully guaranteed; fourth, the analog cordless phone mostly uses discrete components to form a circuit, the degree of integration is not high, the volume is large, and the function consumes more

Therefore, it is difficult to realize, the cost is high, and there is a tendency to be replaced by GSM

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