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CMX865AのメーカーはCMLです、この部品の機能は「DTMF Codec」です。 |
部品番号 | CMX865A |
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部品説明 | DTMF Codec | ||
メーカ | CML | ||
ロゴ | |||
このページの下部にプレビューとCMX865Aダウンロード(pdfファイル)リンクがあります。 Total 30 pages
CMX865A
Telecom Signalling
Device
D/865A/3 February 2007
Provisional Issue
CMX865A – DTMF CODEC AND TELECOM SIGNALLING COMBO
Features
• V.23 1200/75, 1200/1200, 75, 1200 bps FSK
• Bell 202 1200/150, 1200/1200, 150, 1200 bps FSK
• V.21 or Bell 103 300/300 bps FSK
• Low Voice Falsing DTMF Decoder
• DTMF/Tones Transmit and Receive
• Low Power - High Performance
Applications
• Wireless Local Loops
• SMS Phones
• Security Systems
• Remote Utility Meter Reading
• Industrial Control Systems
• Pay-Phones
• Set-Top Boxes
LINE
LINE
INTERFACE
CMX865A
TX USART
FSK MODULATOR
TONE / DTMF GENEwRwAw.TDaOtaRSheet4U.com
RX USART
FSK RECEIVER
TONE / DTMF DETECTOR
C-BUS
SERIAL
INTERFACE
HOST
µC
1. Brief Description
The CMX865A is a multi-standard modem for use in Wireless Local Loop, Short Message Service
telephone based information and telemetry systems. Flexible line driver, hybrid and receiver circuits are
integrated on chip, requiring only passive external components to build a 2 or 4-wire line interface.
A high-quality DTMF decoder with excellent immunity to falsing on voice and a standard DTMF encoder
are included. Alternatively, these blocks can be used to transmit and detect user-specific, programmed
single and dual-tone signals, simple melodies, call progress signals or modem calling and answering
tones.
Host control and data transfer is via a high-speed serial bus that operates in normal and Powersave
modes and which is compatible with most simple types of µC serial interface. An embedded USART
allows multi-format asynchronous data and unformatted synchronous data to be received or transmitted
as 8-bit bytes.
The CMX865A operates from a single 3.0V to 3.6V supply over a temperature range of -40°C to +85°C
and is available in 16-pin SOIC (D4) and 16-pin TSSOP (E4) packages.
© 2007 CML Microsystems Plc
1 Page Telecom Signalling Device
2. Block Diagram
CMX865A
www.DataSheet4U.com
Figure 1 Block Diagram
© 2007 CML Microsystems Plc
3
D/865A/3
3Pages Telecom Signalling Device
CMX865A
4.1. Line Interface (DAA)
A line interface circuit is needed to provide dc isolation and to terminate the line. Typical interface circuits
are described below.
4.1.1. 2-Wire Line Interface
Figure 3 shows a simplified interface for use with a 600Ω 2-wire line. The complex line termination is
provided by R13 and C10, high frequency noise is attenuated by C10 and C11, while R11 and R12 set
the receive signal level into the modem. For clarity the 2-wire line protection circuits have not been shown.
To Ring
Detect
Circuit
+ve
From
hookswitch
driver
R12
R11
RXAFB
C11
RXAN
-
+
VBIAS
2-Wire
Line
1:1 R13
C10
TXA
TXAN
CMX865A
R11
R12
R13
See text
100kΩ
600Ω nominal,
but see text
www.DataSheet4U.com
C10
C11
33nF
100pF
Resistors ±5%, capacitors ±20%
Figure 3 Typical 2-Wire Line Interface Circuit
Resistor R13 is used to match the ac impedance of the interface to the line. With an ideal transformer this
resistor would be equal to the desired impedance (e.g. 600Ω); however in practice with a real transformer,
R13 should be set such that the interface as a whole presents the desired impedance. Line transformer
manufacturers normally provide guidance in this regard.
The transmit line signal level is determined by the voltage swing between the TXA and TXAN pins, less
6dB due to the line termination and less the loss in the line coupling transformer.
Allowing for 1dB loss in the transformer, then with the Tx Mode Register set for a Tx Level Control gain of
0dB the nominal transmit line levels will be:
Tx modem modes
Single tone transmit mode
DTMF transmit mode
VDD = 3.3V
-9.2dBm
-9.2dBm
-5.2 and –7.2 dBm
For a line impedance of 600Ω, 0dBm = 775mVrms. See also section 7.1.3
© 2007 CML Microsystems Plc
6
D/865A/3
6 Page | |||
ページ | 合計 : 30 ページ | ||
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PDF ダウンロード | [ CMX865A データシート.PDF ] |
データシートを活用すると、その部品の主な機能と仕様を詳しく理解できます。 ピン構成、電気的特性、動作パラメータ、性能を確認してください。 |
部品番号 | 部品説明 | メーカ |
CMX865 | FSK Modem and DTMF Codec | CML |
CMX865A | DTMF Codec | CML |