Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
58 words
A device for reducing in-band interference in an r.f. received signal representing digital data, comprising means for filtering interfering signals from the received signal, and means for deciding the most likely digital data to have been transmitted by comparing the filtered received signal with locally generated signals processed in dependence on the estimated response of the communication channel.
Claim 2
Dependent Claim
40 words
A device as claimed in claim 1, in which the filter means is arranged to produce attenuation at frequencies at which the r.f. received signal spectrum has peaks which are not present in the known spectrum of the transmitted signal.
Claim 3
Dependent Claim
38 words
A device as claimed in claim 2, in which the filter means is arranged to produce the attenuation in response to a comparison of the spectrum of the received signal with the known spectrum of the transmitted signal.
Claim 4
Dependent Claim
27 words
A device as claimed in claim 3, in which the filter means is arranged to produce notches of uniform depth at the frequencies at which it attenuates.
Claim 5
Independent Claim
26 words
A device as claimed in any one of claims 1 to 4, in which the received signal represents a digital data stream interspersed with reference samples.
Claim 6
Dependent Claim
36 words
A device as claimed in claim 5, in which in use the estimated response of the channel is updated using the received reference samples and each possible state, locally generated, for each reference sample in turn.
Claim 7
Dependent Claim
73 words
A device as claimed in claim 6, in which in use, for each newly received data sample, a plurality of series of decisions each together with one possible sample state for the newly received sample, are convolved with the impulse response of the estimate of the response of the channel and filter means, in order to obtain the most likely sample state to have been transmitted corresponding to the newly received data sample.
Claim 8
Independent Claim
27 words
A device as claimed in any one of claims 1 to 7, in which the r.f. carrier frequency is in the range of 3 to 30 MHZ.
Claim 9
Independent Claim
12 words
A device substantially as herein described with reference to the accompanying drawings.
Claim 10
Dependent Claim
15 words
A receiver incorporating a device as claimed in any one of claims 1 to 9.