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本文介绍的FM立体声收音机,是由飞利浦公司生产的TDA7088T(电调谐FM接收机电路)、TDA 7040T(FM立体声解码电路)和TDA7050T(低压双声道功放电路)三块集成电路组成。由于这三块集成电路体积微小,所需外围元件少,工作电压低,因而非常适合于制作微型FM立体声收音机。 该FM立体声收音机电路原理如图所示。该电路中,由于TDA7088T采用先进的低中频(70kHz)技术及单变容管单调谐技术,无需使用中频变压器(或中频陶瓷滤波器)以及可变电容器,使其外围电路极为简单,有利于缩小整机体积。其选台功能只需通过按下搜索按钮K1即可实现,由图可知,
This article describes the FM stereo radio, is produced by the Philips TDA7088T (tuned FM receiver circuit), TDA 7040T (FM stereo decoder circuit) and TDA7050T (low-voltage two-channel amplifier circuit) three integrated circuits. Because of the small size of these three integrated circuits, the need for fewer external components, low operating voltage, which is very suitable for the production of miniature FM stereo radio. The FM stereo radio circuit shown in Figure. The circuit, due to the TDA7088T low frequency (70kHz) technology and single-capacitor single-tuned technology, without the use of intermediate frequency transformer (or IF ceramic filter) and variable capacitors, so that the external circuit is very simple, help to narrow Machine size. The function of its station selection just by pressing the search button K1 can be achieved, the figure shows,