AMPS receiver using a zero-IF architecture
AssigneeQUALCOMM Incorporated
InventorsSteven C. Ciccarelli, Arun Raghupathy
Life of this patent
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Abstract
An AMPS receiver system utilizing a ZIF architecture and processing received forward link signals in the digital domain. The AMPS receiver system includes an antenna (105), a direct converter (110), high dynamic A/D converters (120,130), low pass filters (140, 150), a phase shifter (160), a digital VGA (170), a digital FM demodulator (180), an accumulator (185) and a controller (190). The direct converter (110) further includes a low noise amplifier (112), a splitter (113), mixers (114,116) and low pass filters (118,119). The controller (190) adjusts the gains of the low noise amplifier (112) and the digital VGA (170) based on the average power of the signal outputted by the digital VGA (170).
Claims39
Ant AMPS receiver system, comprising:
- an antenna for receiving a radio frequency (RF) signal transmitted from a remote location;
- a direct converter for converting the received RF signal to a baseband signal;
- an analog-to-digital convert (ADC) for converting the baseband signal to a digital baseband signal;
- a digital variable gain amplifier (DVGA) for amplifying the digital baseband signal to generate an amplified digital baseband signal, the DVGA having a DVGA control input for adjusting a gain of the DVGA;
- an accumulator for calculating an average power of the amplified digital baseband signal over a time period;
- a controller for receiving the calculated average power and maintaining the average power to a constant set point by sending a DVGA gain control signal to the DVGA control input to adjust the gain of the DVGA;
- and
- a digital FM demodulator for demodulating the amplified digital baseband signal to retrieve a message signal.
An AMPS receiver circuit, comprising:
- a direct converter for amplifying a received RF signal according to a selected one of a plurality of gains and converting the received RF signal to a baseband signal;
- an analog-to-digital converter (ADC) for converting the baseband signal to a digital baseband signal;
- a phase shifter for changing a phase of the digital baseband signal;
- and
- a controller for sending a phase control signal to the phase shifter to control the phase of the digital baseband signal based in part on a change of the selected one of the plurality of gains.
An AMPS receiver circuit comprising:
- a low noise amplifier (LNA) for amplifying a received RF signal according to a gain from a plurality of discrete gains to generate an amplified RF signal;
- a mixer for converting the amplified RF signal to a baseband signal;
- an analog-to-digital convert (ADC) for converting the baseband signal to a digital baseband signal;
- a phase shifter for changing a phase of the digital baseband signal;
- and
- a controller for controlling the gain of the LNA and the phase change of the phase shifter based in part on a change of the gain of the LNA.
A method of processing a received radio frequency (RF) signal, the method comprising the steps of:
- amplifying the received RF signal by a programmable amplification from a range of amplification levels to generate an amplified RF signal;
- converting the amplified RF signal to a baseband signal;
- converting the baseband signal to a digital baseband signal;
- amplifying the digital baseband signal to generate an amplified digital baseband signal;
- controlling the amplification of the received RF signal and the digital baseband signal based on an average power of the amplified digital baseband signal;
- and
- changing a phase of the digital baseband signal based on a change of the amplification of the RF signal.
A system for processing a received radio frequency (RF) signal, comprising:
- means for amplifying the received RF signal based on a programmable amplification from a plurality of discrete programmable amplification levels to generate an amplified RF signal;
- means for converting the amplified RF signal to a baseband signal;
- means for converting the baseband signal to a digital baseband signal;
- means for amplifying the digital baseband signal to generate an amplified digital baseband signal;
- means for controlling the amplification of the received RF signal and the digital baseband signal based on an average power of the amplified digital baseband signal;
- and
- means for changing a phase of the digital baseband signal based on a change of the amplification of the received RF signal.
Dependencies are inferred from the claim text.