AMIS-50051 Datasheet, PDF (1/7 Pages) AMI SEMICONDUCTOR – Digital Demodulator

AMIS-50051: Digital Demodulator
Wireless Products
Data Sheet
1.0 Introduction
The AMIS-50051 is a small digital demodulator, specially developed to work with the AMIS-50050 spread spectrum baseband
controller. It simplifies the design of the receiver in a direct sequence spread spectrum wireless communication link.
2.0 Key Features
• 1Mbit/s demodulation (QPSK)
• PN code tracking output to AMIS-50050 (Please refer to the AMIS-50050 spread spectrum baseband controller.)
• Fully programmable
• CMOS technology
• Power-down mode
3.0 Applications
• Wireless local area networks
• Portable wireless communication
• Digital cellular telephones
• Wireless ISDN modems
The AMIS-50051 simplifies the design of the receiver in a direct sequence spread spectrum wireless communication link. The AMIS-
50051 uses advanced DSP technology to demodulate the data from a BPSK/DBPSK/QPSK/DQPSK modulated signal. This technique
also provides a PN code tracking signal output, a carrier tracking signal and an automatic gain control (AGC) output signal. The power
of the AMIS-50051 reduces the complexity and component count of a DSSS receiver. The AMIS-50051 is designed to demodulate
QPSK or BPSK data from a carrier whose frequency is11MHz or less. Data rates can be as high as 1Mbit/s for QPSK signals or
500Kbit/s for BPSK signals. An error signal is produced, which can be used to acquire and track the PN code of a direct sequence
spread spectrum system. This output is a voltage, which the AMIS-50050 (please refer to AMIS-50050 spread spectrum baseband
controller) uses to change the phase of the receiver’s PN code. An external despreading device is required to remove the PN code from
the received signal. This reduces the chance of false acquisition over other methods. The AMIS-50051’s internal NCO oscillator is
adjusted by a signal produced from the data demodulation process. This is used to track variations in the carrier frequency of the
received signal.
The AMIS-50051 produces a level error output. This output is pulsed high or low depending on the level of the received signal. This can
be used to form an AGC circuit.
The AMIS-50051 requires few external components. The AMIS-50051 is designed to work directly with the AMIS-50050 to simplify the
design effort of a wireless communication link.
AMI Semiconductor – Sept. 06
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