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參數資料
| 型號： | MM74HC942J |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 調制器/解調器 |
| 英文描述： | MM74HC942 is a full duplex low speed modem |
| 中文描述： | 0.3 kbps DATA, MODEM, CDIP20 |
| 封裝： | DIP-20 |
| 文件頁數： | 1/8頁 |
| 文件大小： | 146K |
| 代理商： | MM74HC942J |
TL/F/5348
M
January 1988
MM74HC942 300 Baud Modem
General Description
The MM74HC942 is a full duplex low speed modem. It pro-
vides a 300 baud bidirectional serial interface for data com-
munication over telephone lines and other narrow band-
width channels. It is Bell 103 compatible.
The MM74HC942 utilizes advanced silicon-gate CMOS
technology. Switched capacitor techniques are used to per-
form analog signal processing.
MODULATOR SECTION
The modulator contains a frequency synthesizer and a sine
wave synthesizer. It produces a phase coherent frequency
shift keyed (FSK) output.
LINE DRIVER AND HYBRID SECTION
The line driver and hybrid are designed to facilitate connec-
tion to a 600
X
phone line. They can perform two-to-four-
wire conversion and drive the line at a maximum of 0 dBm.
DEMODULATOR SECTION
The demodulator incorporates anti-aliasing filters, a receive
filter, limiter, discriminator, and carrier detect circuit. The
nine pole receive filter provides 60 dB of transmitted tone
rejection. The discriminator is fully balanced for stable
operation.
Features
Y
Drives 600
X
at 0 dBm
Y
All filters on chip
Y
Transmit level adjustment compatible with universal
service order code
Y
TTL and CMOS compatible logic
Y
All inputs protected against static damage
Y
g
5V supplies
Y
Low power consumption
Y
Full duplex answer or originate operation
Y
Analog loopback for self test
Y
Power down mode
Applications
Y
Built-in low speed modems
Y
Remote data collection
Y
Radio telemetry
Y
Credit verification
Y
Stand-alone modems
Y
Point-of-sale terminals
Y
Tone signalling systems
Y
Remote process control
TRI-STATE
é
is a registered trademark of National Semiconductor Corp.
Connection and Block Diagrams
Dual-In-Line Package
TL/F/5348–1
Top View
Order Number MM54HC942 or
MM74HC942
TL/F/5348–2
C
1995 National Semiconductor Corporation
RRD-B30M105/Printed in U. S. A.
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相關代理商/技術參數 |
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| MM74HC942N | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:MM74HC942 is a full duplex low speed modem |
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