Receiver and Methods for Calibration Thereof
AssigneeCambridge Silicon Radio Limited
InventorsSimon Chang, Erik Lindskog, Hong Wan, Rainer Herberholz
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Abstract
There is disclosed a receiver and associated methods in which a received signal can be sampled at the symbol rate rather than oversampled. This reduction in the sampling frequency compared with conventional receivers lowers power consumption. Quality metrics in receiving the data (e.g. packet error rate, etc) are not adversely affected by setting a programmable phase shift in the sampling frequency. The programmable shift can be selected through a calibration process using a known sequence of symbols, such as the short training field in 802.11 standards.
Claims13
A receiver, comprising:
- an input, for receiving a received signal having a symbol rate;
- a clock input, for receiving a clock signal;
- phase shift means, for applying a programmable phase shift to said clock signal;
- and
- an analogue to digital converter, for sampling the received signal at the symbol rate and in accordance with transitions in the phase-shifted clock signal, and generating a sampled signal.
A method of calibrating a receiver, the receiver comprising an input, for receiving a received signal having a symbol rate;
- a clock input, for receiving a clock signal;
- phase shift means, for applying a programmable phase shift to said clock signal;
- and an analogue to digital converter, for sampling the received signal at the symbol rate and in accordance with transitions in the phase-shifted clock signal, and generating a sampled signal, the method comprising:
- detecting the presence of a first repetition of a known sequence of symbols in the received signal, and measuring a first correlation strength;
- altering the programmable phase shift to a different value;
- detecting the presence of a second repetition of a known sequence of symbols in the received signal, and measuring a second correlation strength;
- comparing the first correlation strength to the second correlation strength;
- and
- on the basis of the comparison, selecting the programmable phase shift.
Dependencies are inferred from the claim text.