晶體三極管開關(guān)混頻電路研究
2020年電子技術(shù)應(yīng)用第9期
張宏強，王 勇，劉乃安
西安電子科技大學 通信工程學院，陜西 西安710071
摘要： 針對傳統(tǒng)的乘法器混頻方式受本振信號影響，且存在很多干擾和失真，很大程度影響接收機的性能，采用晶體三極管開關(guān)混頻方法解決這一問題。詳細推導(dǎo)了開關(guān)混頻的數(shù)學公式，通過對方波信號進行傅里葉級數(shù)展開，提出了I型、II型開關(guān)混頻的數(shù)學模型，并針對NPN三極管開關(guān)電路提出設(shè)計方案。在Multisim軟件環(huán)境中實施了仿真驗證，以AM信號為例進行三極管開關(guān)混頻，引入加速電容消除了電路的負峰切削失真,并濾出中頻信號，仿真結(jié)果較為理想。理論和實踐表明，基于晶體三極管開關(guān)的混頻方式避免了本振信號的干擾，可提高接收機性能。
中圖分類號： TN710.2
文獻標識碼： A
DOI：10.16157/j.issn.0258-7998.200240
中文引用格式： 張宏強，王勇，劉乃安. 晶體三極管開關(guān)混頻電路研究[J].電子技術(shù)應(yīng)用，2020，46(9)：127-131，136.
英文引用格式： Zhang Hongqiang，Wang Yong，Liu Naian. Research on BJT switch mixing circuit[J]. Application of Electronic Technique，2020，46(9)：127-131，136.
文獻標識碼： A
DOI：10.16157/j.issn.0258-7998.200240
中文引用格式： 張宏強，王勇，劉乃安. 晶體三極管開關(guān)混頻電路研究[J].電子技術(shù)應(yīng)用，2020，46(9)：127-131，136.
英文引用格式： Zhang Hongqiang，Wang Yong，Liu Naian. Research on BJT switch mixing circuit[J]. Application of Electronic Technique，2020，46(9)：127-131，136.
Research on BJT switch mixing circuit
Zhang Hongqiang，Wang Yong，Liu Naian
School of Telecommunications Engineering，Xidian University，Xi′an 710126，China
Abstract： In allusion to the problem that traditional multiplier mixing method is affected by local oscillator and there exists interferences and distortions, which greatly affects the performance of receiver, a bipolar junction transistor(BJT) switch mixing method is proposed. The mathematical formula of switch mixing is deduced in detail, and two mathematical models, I-type and II-type switch mixing models are proposed by using Fourier series expansion of square wave. Based on NPN BJT switch, a mixing circuit is designed, and simulation is carried out on Multisim software environment. AM signal is used as an example to mix on BJT switch. Acceleration capacitor is added to eliminate negative peak cutting distortion and intermediate frequency signal is filtered out. The results of simulation are ideal. It is proved theoretically and practically that BJT switch mixing method prevents the interference of local oscillator signal, which can enhance receiver performance.
Key words : bipolar junction transistor；mixing；local oscillator signal；Fourier series；acceleration capacitor
0 引言
混頻一般通過非線性元件或者專用的集成電路乘法器來實現(xiàn)，混頻信號的幅度和相位信息受本振信號影響，并且也會引入很多干擾和失真，這些都會降低接收機的性能[1]。開關(guān)混頻方式可解決以上問題，且晶體三極管廉價易得，開關(guān)電路易于實現(xiàn)，原理如圖1所示。
本文詳細內(nèi)容請下載:http://m.xxav2194.com/resource/share/2000003001
作者信息:
張宏強，王 勇，劉乃安
(西安電子科技大學 通信工程學院，陜西 西安710071)
此內(nèi)容為AET網(wǎng)站原創(chuàng)，未經(jīng)授權(quán)禁止轉(zhuǎn)載。