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73K324L 参数 Datasheet PDF下载

73K324L图片预览
型号: 73K324L
PDF下载: 下载PDF文件 查看货源
内容描述: 单芯片调制解调器 [Single-Chip Modem]
分类和应用: 调制解调器
文件页数/大小: 30 页 / 239 K
品牌: TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
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73K324L  
CCITT V.22bis,V.23,V.22,V.21, Bell 212A  
Single-Chip Modem  
DATA SHEET  
incoming signal. Adaptive equalization corrects for  
varying line conditions by automatically changing  
filter parameters to compensate for line  
characteristics.  
DESCRIPTION (continued)  
The 73K324L offers full hardware and software  
compatibility with other products in TERIDIAN  
Semiconductor's K-Series family of single-chip  
modems, allowing system upgrades with a single  
component change. The 73K324L is ideal for use in  
free-standing or integral system modem products  
where full-duplex 2400 bit/s operation with Alternate  
mode capability is required. Its high functionality, low  
power consumption, and efficient packaging simplify  
design requirements and increase system reliability.  
A complete modem requires only the addition of the  
phone line interface, a control microprocessor, and  
RS-232 level converters for a typical system.  
DPSK MODULATOR/DEMODULATOR  
The 73K324L modulates a serial bit stream into  
di-bit pairs that are represented by four possible  
phase shifts as prescribed by the Bell 212A/V.22  
standards. The baseband signal is then filtered to  
reduce intersymbol interference on the bandlimited  
2-wire PSTN line. Transmission occurs on either a  
1200 Hz (Originate mode) or 2400 Hz carrier  
(Answer mode). Demodulation is the reverse of the  
modulation process, with the incoming analog signal  
eventually decoded into di-bits and converted back  
to a serial bit stream. The demodulator also recovers  
the clock, which was encoded into the analog signal  
during modulation. Demodulation occurs using either  
a 1200 Hz carrier (Answer mode or ALB Originate  
mode) or a 2400 Hz carrier (Originate mode or ALB  
Answer mode). The 73K324L use a phase locked  
loop coherent demodulation technique that offers  
excellent performance. Adaptive equalization is also  
used in DPSK modes for optimum operation with  
varying lines.  
The 73K324L is designed to provide a complete  
V.22bis, V.22, Bell 212A, V.21, and V.23 compatible  
modem on a chip. Many functions were included to  
simplify implementation in typical modem designs. In  
addition to the basic 2400 bit/s QAM, 1200/600 bit/s  
DPSK  
and  
1200/300/75  
bit/s  
FSK  
modulator/demodulator sections, the device also  
includes synch/asynch buffering, DTMF, answer,  
soft carrier, guard, and calling tone generator  
capabilities. Handshake pattern detectors simplify  
control of connect sequences, and precise tone  
detectors allow accurate detection of call progress,  
answer, calling, and soft carrier turn off tones. All  
Operating modes defined by the incorporated  
standards are included, and Test modes are  
provided. Most functions are selectable as options,  
and logical defaults are provided. The device can be  
directly interfaced to a microprocessor via its 8-bit  
multiplexed address/data bus for control and status  
monitoring. Data communications takes place  
through a separate serial port. Data may also be  
sent and received through the control registers. This  
simplifies designs requiring speed buffering, error  
control and compression.  
FSK MODULATOR/DEMODULATOR  
The FSK modulator/demodulator produces  
a
frequency modulated analog output signal using two  
discrete frequencies to represent the binary data.  
V.21 frequencies of 980 and 1180 Hz (originate  
mark and space), or 1650 and 1850 Hz (answer  
mark and space) are used in V.21 mode. V.23 mode  
uses 1300 and 2100 Hz for the main channel or 390  
and 450 Hz for the back channel. Demodulation  
involves detecting the received frequencies and  
decoding them into the appropriate binary value.  
The rate converter and scrambler/descrambler are  
automatically bypassed in the FSK modes.  
FUNCTIONAL DESCRIPTION  
QAM MODULATOR/DEMODULATOR  
PASSBAND FILTERS AND EQUALIZERS  
The 73K324L encodes incoming data into quad-bits  
represented by 16 possible signal points with  
specific phase and amplitude levels. The baseband  
signal is then filtered to reduce intersymbol  
interference on the bandlimited telephone network.  
The modulator transmits this encoded data using  
either a 1200 Hz (Originate mode) or 2400 Hz  
(Answer mode) carrier. The demodulator, although  
more complex, essentially reverses this procedure  
while also recovering the data clock from the  
High and low band filters are included to shape the  
amplitude and phase response of the transmit and  
receive signals and to provide compromise delay  
equalization as well as rejection of out-of-band  
signals. The transmit signal filtering corresponds to a  
&%%  
raised  
characteristic.  
cosine  
frequency  
response  
Page: 2 of 30  
© 2005, 2008 TERIDIAN Semiconductor Corporation  
Rev 7.1