US 6,650,712 B1Granted

Low complexity method and apparatus for FSK signal reception

Assignee3Com Corporation

InventorsAlexandre Leonidov, Vitali Vinokour, Benjamin Dolnik

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Abstract

Disclosed is an apparatus and method for low complexity, phase independent reception of FSK signals. A finite series of delay elements produces a plurality of equidistant samples of a received FSK signal. The plurality of equidistant samples is processed by an arithmetic unit using a phase independent algorithm to obtain an estimate of the received signal. The estimate of the received signal is then compared to a threshold value to determine if the estimate corresponds to a binary 1 or binary 0, which increments a counter corresponding to each binary value. Multiple estimates are counted over a baud interval of the received FSK signal and a binary 1 or binary 0 is output as a received data signal value depending upon which binary value the counter having the higher value corresponds to.

Claims27

Dependent claims

A receiver for receiving a FSK signal having a first frequency corresponding to a binary “0” and a second frequency corresponding to a binary “1”, the receiver comprising:

a finite series of delay elements, each element having an input and an output terminal and being configured to introduce a predetermined delay interval corresponding to a sampling period of the received signal, and where the input terminal of a first element of the finite series of delay elements is coupled to an input terminal of the receiver;
an arithmetic unit having a plurality of input terminals and an output terminal, where a first one of the plurality of input terminals is coupled to the input terminal of the first element of the finite series of delay elements and where each remaining one of the plurality of input terminals is coupled to the output terminal of a corresponding one of the delay elements, where the arithmetic unit is configured to generate a metric signal at the output terminal of the arithmetic unit using a phase independent equation;
and
an integration and decision unit having an input terminal coupled to the output terminal of the arithmetic unit, where the integration and decision unit is configured to compare the metric signal to a threshold value to obtain a binary sample and integrate multiple binary samples in a baud interval of the FSK signal in order to generate a binary data signal at an output terminal of the integration and decision unit.

1 more element

Dependencies are inferred from the claim text.