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随着数字通信技术的发展,在有线通信、无线通信、计算机通信等领域都需要使用调制解调器。本文介绍一种美国AMD公司(ADVANCED MICRODEVICES)在80年代初设计制造的可编程式异步频移键控(FSK)调制解调器AM7910,它利用大规模NMOS集成技术,在一片芯片内有数字滤波器、A/D和D/A转换电路、接中联络信号、自动应答、反馈环路和反向通信信道,并设有多种工作方式,可与Bell103/202,CCITTV.21/V.23等规程指标兼容,可用引脚选择的方式控制300、600、1200波特的传输速率,可实现全双工传输,同时,它提供了标准接口,可与许多种微处理器系统兼容。所有的数据接口都与TTL电平兼容。 AM7910为28管脚双列直插式封装,外接1个晶体和4个廉价的、要求不严格的外部补偿元图1 AM7910管脚排列图件,使用±5V双电源供电,其管脚排列如图1所示。管脚功能简述如下:脚1(RING)为振铃端;脚2
With the development of digital communication technology, modems are needed in the fields of wired communication, wireless communication and computer communication. This article presents a AM7910 Programmable Asynchronous Frequency Shift Keying (FSK) modem ADVANCED MICRODEVICES designed in the early 1980s using a large scale NMOS integrated technology with digital filters in a chip, A / D and D / A conversion circuit, connect the contact signal, automatic response, feedback loop and reverse communication channel, and has a variety of ways to work with Bell103 / 202, CCITTV.21 / V.23 and other indicators Compatible with pin-selectable control of 300,600,1200 baud transfer rates for full duplex transmission while providing a standard interface that is compatible with many microprocessor systems. All data interfaces are TTL-level compatible. The AM7910 is a 28-pin dual in-line package with an external crystal and four low-cost, uncommanded external compensation elements. Figure 1. AM7910 pinout diagram using ± 5V dual supplies with pinouts such as Figure 1 shows. Pin functions as follows: pin 1 (RING) ring terminal;