Radio frequency communication
AssigneeBAE SYSTEMS plc
InventorsAndrew James Smith, Mark Trevor Newmann
Life of this patent
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Abstract
An analogue modem circuit and carrier recovery method are disclosed for use between an RF receiver and a digital modem circuit configured for receiving a baseband RF input signal, and including an up-converter with frequency supplied by an up-converter voltage controlled oscillator, VCO; a down-converter with frequency supplied by a down-converter VCO; a Costas loop sub-module; and baseband outputs from the down-converter to a digital modem circuit. The up-converter feeds the down-converter, and the Costas loop module performs Costas loop functionality on the output of the down-converter to control the up-converter VCO frequency output to thereby control modification of rotation of symbols of the baseband signal.
Claims13
An analogue modem circuit for use between a radio frequency receiver and a digital modem circuit, the analogue modem circuit comprising:
- inputs for receiving a baseband RF input signal from an RF receiver;
- an up-converter with frequency supplied by an up-converter voltage controlled oscillator (VCO);
- a down-converter with frequency supplied by a down-converter VCO;
- a Costas loop sub-module;
- and
- outputs for outputting baseband outputs from the down-converter to a digital modem circuit;
- wherein:
- the up-converter is arranged to feed the down-converter, and the Costas loop module is configured to perform Costas loop functionality on the output of the down-converter to control the up-converter VCO frequency output to thereby control modification of rotation of symbols of the baseband RF input signal as it is up-converted and then down-converted to provide the baseband outputs.
A carrier recovery method performed by an analogue modem circuit for use between a radio frequency (RF) receiver and a digital modem circuit, the method comprising:
- receiving a baseband RF input signal from an RF receiver at inputs of the analogue modem circuit;
- supplying, via an up-converter voltage controlled oscillator (VCO), a frequency to an up-converter;
- supplying, via a down-converter VCO, a frequency to a down-converter;
- feeding the down-converter from the up-converter;
- performing, via a Costas loop module, Costas loop functionality on an output of the down-converter to control the up-converter VCO frequency output to thereby control modification of rotation of symbols of the baseband RF input signal as it is up-converted and then down-converted to provide baseband outputs;
- and
- outputting, from the analogue modem circuit, the baseband outputs.
One or more processors arranged to operate in accordance with a carrier recovery method performed by an analogue modem circuit for use between a radio frequency (RF) receiver and a digital modem circuit, the method comprising:
- receiving a baseband RF input signal from an RF receiver at inputs of the analogue modem circuit;
- supplying, via an up-converter voltage controlled oscillator (VCO), a frequency to an up-converter;
- supplying, via a down-converter VCO, a frequency to a down-converter;
- feeding the down-converter from the up-converter;
- performing, via a Costas loop module, Costas loop functionality on an output of the down-converter to control the up-converter VCO frequency output to thereby control modification of rotation of symbols of the baseband RF input signal as it is up-converted and then down-converted to provide baseband outputs;
- and
- outputting, from the analogue modem circuit, the baseband outputs.
Dependencies are inferred from the claim text.