A circuit for detecting and synchronizing a ghost cancellation reference (GCR) signal in a television video signal, includes a circuit for receiving at least one field of an input video signal, a circuit for finding a maximum correlation peak value in a field of said input video signal, a circuit for scaling the maximum correlation peak value to a lower predetermined value for detection for forming a scaled peak value, a circuit for synchronizing a next field of the video signal using the scaled peak value, and a circuit for predicting a future position of the GCR signal.

Improved signal reception is provided in a digital television signal received by identifying and mitigating multipath signal effects prior to demodulation and equalization. According to an exemplary embodiment, a digital television signal is received having multipath signal effects which cause a plurality of ripples in the received signal. The amplitude of at least one of the ripples and the frequency separation between at least two of the ripples are detected. At least one of an antenna and a tuner is controlled in dependence upon the detection. Signal demodulation and equalization operations may be performed after at least one of the antenna and the tuner is controlled.

RF programmable SAW filters achieve selectable filter performance by providing tunable input and output interdigital (IDTs) with different synchronous frequencies and substantially reduce electromagnetic interference (EMI) associated with RF signals not of interest. The RF programmable SAW filter includes tunable input and output IDT's, with the input and output IDT's having different input and output IDT synchronous frequencies. The input signal is divided into multiple output signals along multiple signal paths that are applied to an input tap weight network wherein the amplitude of each output signal may be varied individually. The individually weighted signal paths are then applied one each to individual IDT input electrode fingers in a means for IDT input, which is characterized by a synchronous frequency F.sub.in. The IDT input means generates an acoustic wave that propagates to a means for IDT output, which is characterized by a synchronous frequency F.sub.out, where F.sub.in and F.sub.out are not the same. The electrical signals generated in the IDT output means are processed through an output tap weight network, and the output signal is formed as a weighted sum to provide a selectable center frequency, a selectable bandwidth, a minimum insertion loss, a maximum sidelobe rejection level and a selectable filter transfer function, or phase/magnitude profile.RF programmable SAW filters, RF partially programmable SAW filters, RF fully programmable SAW filters and a method for making programmable RF SAW filters are provided.

Apparatus for performing time and frequency-domain filtering in a sampled communication channel for the transmission of binary information. A received signal is provided to a double-domain, analog transversal equalizer comprising a plurality of serially connected, active, analog filter sections with associated tap locations, each filter section having a programmable frequency response and adaptively controlled one-bit delay. The filter sections provide sequential, cumulative frequency domain filtering as the received signal propagates through the equalizer. The transfer function of each filter section has a linear phase polynomial denominator and a real (at s=j.omega.) polynomial numerator, facilitating independent control of the delay and frequency response of each filter section. A plurality of analog multipliers multiply signals present at the tap locations by analog tap weight signals to generate a plurality of product signals, and an analog summer adds the product signals to generate an output filtered signal before sampling occurs. An LMS error-based adaptive tap weight control circuit iteratively generates optimal analog tap weight signals, a delay control circuit provides the necessary timing signals at the bit-rate to control the time delay of each analog filter section and a location of zeros circuit controls the location of zeros in the transfer function, and hence the frequency response, of each filter section. The double-domain transversal equalizer provides aperiodic and controlled frequency response at low frequencies and does not require a noise suppressing prefilter.

An analog, adaptive generalized transversal equalizer for use in the filtering system of a disc drive PRML read channel, the transversal equalizer employing the use of non-ideal delay elements. The filtering system comprises the equalizer connected in series with an adaptive, analog prefilter. The prefilter is comprised of a plurality of serially connected, adaptive, analog filter stages having variable transfer functions determined by adaptive parameter signals received by the filter stages. The generalized transversal equalizer comprises a plurality of serially connected, adaptive, analog low pass filters, having taps on either side of each low pass filter, a plurality of multipliers that receive signals at the tap locations of the delay circuit, and a summing circuit that receives the outputs of the multipliers. The transfer functions of the delay circuit are continuously variable in relation to adaptive parameter signals received by the delay circuit and the coefficients of multiplication are variable in relation to the adaptation process.