Modulation circuit and communication device

Abstract

The invention discloses a modulation circuit which comprises a digital circuit portion and an analog circuit portion. In the digital circuit portion, baseband signals are used for digitally modulating square waves, low-medium frequency signals based on square wave modulation are outputted and are inputted to a frequency mixer without passing through a D / A (digital-to-analog) circuit, frequencies of the low-medium frequency signals and local oscillator signals generated by a frequency synthesizer are mixed, and then the low-medium frequency signals are outputted by a band-pass filter and an amplifier. By the aid of the mode, procedures of testing and adjusting carrier leakage can be decreased, the D / A circuit is omitted, the structural size of the modulation circuit can be effectively reduced, cost and power consumption are reduced, production efficiency is improved, and miniaturization application is facilitated. The invention further discloses a communication device comprising the modulation circuit.

Description

Technical field [0001] The present invention relates to the field of radio communication, in particular to a modulation circuit, and also to a communication device using the modulation circuit. Background technique [0002] At present, modulation circuits in satellite, navigation, mobile and other radio communication equipment usually include a digital circuit part and an analog circuit part, and the digital circuit part and the analog circuit part are connected by a digital / analog (D / A) conversion circuit. Among them, the digital circuit part is mainly composed of programmable electronic components, such as a field programmable logic gate array (FPGA), which is used to complete functions such as framing and encoding of the data to be sent, forming a digital baseband signal and outputting it. [0003] The digital baseband signal output from the digital circuit part usually needs to go through a digital / analog (D / A) conversion circuit. The function of the D / A conversion circuit is t...

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Problems solved by technology

[0005] It can be seen that in the prior art of the modulation circuit, the digital baseband signal output by the digital circuit part needs to be modulated after the D / A, such as BPSK, QPSK modulation, etc., this modulation method for the analog carrier is in During the implementation process, there will be problems such as carrier modulation deviation caused by the influence of external conditions such as analog carrier leakage and ambient temperature on electronic components. Usually, it is necessary to test and adjust the modulation circuit to ensure the effectiveness and consistency of the modulation circuit.

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