描述 Description

The CD22202 and CD22203 complete dual-tone multiple frequency (DTMF) receivers detect a selectable group of 12 or 16 standard digits. No front-end pre-filtering is needed. The only externally required components are an inexpensive 3.579545MHz TV “colorburst’’ crystal (for frequency reference) and a bias resistor. Extremely high system density is possible through the use of the clock output of a crystal connected CD22202/CD22203 receiver to drive the time bases of additional receivers. This is a monolithic integrated circuit fabricated with low-power, complementary symmetry CMOS processing. It only requires a single low tolerance power supply.

特性 Features

? Central Office Quality

? No Front End Band Splitting Filters Required

? Single, Low Tolerance, 5V Supply

? Detects Either 12 or 16 Standard DTMF Digits

? Uses Inexpensive 3.579545MHz Crystal for Reference

? Excellent Speech Immunity

? Output in Either 4-Bit Hexadecimal Code or Binary

Coded 2-of-8

? Synchronous or Handshake Interface

? Three-State Outputs

? Excellent Latch-Up Immunity