- 您现在的位置：买卖IC网 > PDF目录166217 > AM79Q021VC (ADVANCED MICRO DEVICES INC) PCM CODEC, PQFP44 PDF资料下载
参数资料
| 型号： | AM79Q021VC |
| 厂商： | ADVANCED MICRO DEVICES INC |
| 元件分类： | 编解码器 |
| 英文描述： | PCM CODEC, PQFP44 |
| 封装： | TQFP-44 |
| 文件页数： | 57/64页 |
| 文件大小： | 911K |
| 代理商： | AM79Q021VC |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页当前第57页第58页第59页第60页第61页第62页第63页第64页
60
Am79Q02/021/031 Data Sheet
APPLICATIONS
The QSLAC device performs a programmable codec/
filter function for four telephone lines. It interfaces to the
telephone lines through an AMD SLIC device or a
transformer with external buffering. The QSLAC device
provides latched digital I/O to control and monitor four
SLICs and provides access to time-critical information,
like off/on-hook and ring trip, for all four channels via a
single read operation. When various country or
transmission requirements must be met, the QSLAC
device enables a single SLIC design for multiple
applications. The line characteristics (such as apparent
impedance, attenuation, and hybrid balance) can be
modified by programming each QSLAC device
channel’s coefficients to meet desired performance.
The QSLAC device requires an external buffer to drive
transformer SLICs.
Connection to a PCM back plane is implemented by
means of a simple buffer chip. Several QSLAC devices
can be tied together in one bus interfacing the back
plane through a single buffer. An intelligent bus
interface chip is not required because each QSLAC
device provides its own buffer control (TSXA/B). The
Q S LAC de v i ce is c ontr o l l ed thr ough the
microprocessor interface, either by a microprocessor
on the linecard or by a central processor.
Controlling the SLIC
T he A m 79 Q0 21 Q S LAC dev ic e ha s fi ve T TL -
compatible I/O pins (CD1, CD2, C3 to C5) for each
channel. The Am79Q031 QSLAC device has only CD1
and CD2 available. The outputs are programmed
using Command 19, and the status is read back using
Command 20. CD1 and CD2 for all four channels can
be read back using Command 16. The direction of the
I/O pins (input or output) is specified by programming
the SLIC I/O direction register (Commands 21 and 22).
Default Filter Coefficients
The default filter coefficients were calculated assuming an
Am7920 SLIC with 50
protection resistors, a 178 k
transversal impedance (ZT), and a 90.5 k receive
impedance (ZRX). This SLIC has a transmit gain of 0.5
(GTX) and a current gain of 500 (K1). The transmit
relative level was set to +0.28 dBr, and the receive
relative level was set to –4.39 dBr. The equalization
filters (X and R) were not optimized. The balance filter
was designed to give acceptable balance into a variety
of impedances. The nominal input impedance was set
to 815
. If the SLIC circuit differs significantly from this
design, the default filters cannot be used and must be
replaced by programmed coefficients.
Calculating Coefficients with WinSLAC Software
The WinSLAC software is a program that models the
QSLAC device, the line conditions, the SLIC, and the
linecard components to obtain the coefficients of the
programmable filters of the QSLAC device and some
of the transmission performance plots.
The following parameters relating to the desired line
conditions and the components/circuits used in the
linecard are to be provided as input to the program:
1. Line impedance or the balance impedance of the
line is specified by the local PTT.
2. Desired two-wire impedance that is to appear at the
linecard terminals of the exchange.
3. Tabular data for templates describing the frequency
response and attenuation distortion of the design.
4. Relative analog signal levels for both the transmit
and receive two-wire signals.
5. Component values and SLIC device selection for
the analog portion of the line circuits.
6. Two-wire return loss template is usually specified
by the local PTT.
7. Four-wire return loss template is usually specified
by the local PTT.
The output from the WinSLAC program includes the
coefficients of the GR, GX, Z, R, X, and B filters as
well as transmission performance plots of two-wire
return loss, receive and transmit path frequency
responses, and four-wire return loss.
The software supports the use of the AMD SLICs or
allows entry of a SPICE netlist describing the behavior
of any type of SLIC circuit.
相关PDF资料 |
PDF描述 |
|---|---|
| AM79Q062JC | A/MU-LAW, PCM CODEC, PQCC32 |
| AM80A-048L-050P25 | 1-OUTPUT 125 W DC-DC REG PWR SUPPLY MODULE |
| AM8152BDC | SPECIALTY INTERFACE CIRCUIT, CDIP48 |
| AMB315218 | MOTION SENSOR, XSS |
| AMCY-ED12566/1 | 880 MHz - 915 MHz RF/MICROWAVE DOUBLE BALANCED MIXER |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AM79Q02JC | 制造商:Advanced Micro Devices 功能描述: |
| AM79Q031 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Quad Subscriber Line Audio-Processing Circuit (QSLAC) Devices |
| AM79Q031JC | 制造商:Advanced Micro Devices 功能描述: |
| AM79Q061JC | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Telecommunication IC |
| AM79Q061VC | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Telecommunication IC |
发布紧急采购，3分钟左右您将得到回复。