Signal processing system and method
First Claim
1. A signal processing system comprising a plurality of input channels, sampling means adapted to obtain a first signal sample from at least a first of the plurality of input channels at a first time and a second signal sample from a second of the plurality of input channels at a second time, switching means for switching said sampling means between input channels, and processing means for processing said signal samples, the processing means being arranged to generate an output suitable for sending to beamforming means, said output being related to at least one weighting co-efficient associated with at least one of said input channels and being generated using an iteration of an error minimisation routine executed by the processing means using said first signal sample to cause a first output at a first time and using said second signal sample to cause a second output at a second time wherein the sampling means is arranged to sample each input channel in a predetermined order and the processing means is arranged to determine an input channel which makes a significant contribution to a gradient of an error function and to use a signal from said channel in the error minimisation routine
3 Assignments
0 Petitions
Accused Products
Abstract
A phased array antenna that employs a switched least means squared architecture comprises plurality of receiving elements each having a respective weighting unit associated therewith, a summation unit, a processor, a plurality of sampling devise and a switching unit contains a switch arm having a contact at its free and, an ADC and a plurality of switch contacts corresponding to the ends of channels connected to the respective sampling devices. Each of a plurality of receiving elements is ampled by a respective sampling device prior to an incoming signal subjected to complex weighting by respective weighting units. Each of the signals sampled by the sampling device passes along respective channels to the switching unit. Thus, by switching between the contacts it is possible to vary which of the receiving elements is sampled. The processor calculates new complex weighting coefficients to be applied to the incoming signals by the weighting units using the sampled incoming signals in order to minimize a difference between an output from the summation unit y and a training signal d.
-
Citations
25 Claims
- 1. A signal processing system comprising a plurality of input channels, sampling means adapted to obtain a first signal sample from at least a first of the plurality of input channels at a first time and a second signal sample from a second of the plurality of input channels at a second time, switching means for switching said sampling means between input channels, and processing means for processing said signal samples, the processing means being arranged to generate an output suitable for sending to beamforming means, said output being related to at least one weighting co-efficient associated with at least one of said input channels and being generated using an iteration of an error minimisation routine executed by the processing means using said first signal sample to cause a first output at a first time and using said second signal sample to cause a second output at a second time wherein the sampling means is arranged to sample each input channel in a predetermined order and the processing means is arranged to determine an input channel which makes a significant contribution to a gradient of an error function and to use a signal from said channel in the error minimisation routine
-
9. A method of signal processing comprising the steps of:
- a method of signal processing comprising the steps of;
i) sampling a sample signal of a subset of a plurality of input channels;
ii) reducing an error function using said sample, using digital processing means;
iii) switching between the subset and another subset of the plurality of input channels using switching means, or resampling the same subset as in step (i); and
iv) determining which of the input channels make significant contributions to a gradient of the error function and switching to a subset of the plurality of input channels including at least one of said channels prior to step (iii). - View Dependent Claims (10, 11, 12, 13, 14, 15, 18)
- a method of signal processing comprising the steps of;
- 19. An adaptive filter comprising a plurality of input channels, a switch, a processor, said switch being arranged to switch a subset of said input channels in and out of operative communication with the processor such that said processor processes sample signals from different channels at different times.
- 23. A method of adaptive filtering comprising obtaining a sample signal, or signals, from a plurality of channels and using the sample signals to form at least one weighting coefficient for at least one of the channels, the weighting coefficients being obtained by performing an error function reduction iteration associated with the difference between the sampled signal, or signals, and a reference values, the error function being reduced by operating on a sample signal, or signals, from a subset of the available channels that is smaller than the number of available channels, and changing the channel, or channels, present in the subset between at least two iterations of the reduction of the error function.
Specification