Abstract: A channel equalizer obtains channel impulse responses (CIRs) for all subcarriers by way of filtering channel impulse responses of specific subcarriers using at least two filters. One of the two filters may be a low pass filter. At least one other of the at least two filters is implemented as a band pass filter having a variable filtering bandwidth, being available to establish various filtering bandwidths in response to various multi-path channel environments. By improving the performance of channel estimation, equalization may be improved.

Abstract: A method, apparatus and computer program for detecting an echo signal including interpolating at least one fast Fourier transformed OFDM signal received in the time-domain, interpolating the at least one signal generated by the time-domain interpolation in the frequency-domain, using a time-domain varying bandwidth low pass filter (LPF), with bandwidth that varies in response to a bandwidth control signal, measuring at least one signal to power ratio between a scattered pilot signal of the at least one signal generated by the time-domain interpolation and another scattered pilot signal of the at least one signal generated by the frequency-domain interpolation, and comparing the signal to power ratio to a threshold value to determine a state of an echo signal, and providing the bandwidth control signal with the determined echo state information to adjust the bandwidth of the time-domain LPF, based on the bandwidth control signal.

Abstract: DVB-T receivers and methods may provide automatic detection of spectrum inversion using continual pilot correlation. A DVB-T receiver may include a demodulator, a fast Fourier transformation (FFT) unit, and a spectrum inversion detector. The demodulator may demodulate a received DVB-T digital signal according to a spectrum inversion signal, and the FFT unit may perform fast Fourier transformation (FFT) on the demodulated signal. The spectrum inversion detector may calculate continual pilot correlation values for the FFT-processed signal and may generate the spectrum inversion signal to indicate whether spectrum inversion has occurred according to the calculated correlation values. The DVB-T receiver may perform normal correlation and position inversion correlation on continual pilots using a spectrum inversion detector to automatically detect whether spectrum inversion has occurred. Related methods are also discussed.

Abstract: DVB-T receivers and methods may provide automatic detection of spectrum inversion using continual pilot correlation. A DVB-T receiver may include a demodulator, a fast Fourier transformation (FFT) unit, and a spectrum inversion detector. The demodulator may demodulate a received DVB-T digital signal according to a spectrum inversion signal, and the FFT unit may perform fast Fourier transformation (FFT) on the demodulated signal. The spectrum inversion detector may calculate continual pilot correlation values for the FFT-processed signal and may generate the spectrum inversion signal to indicate whether spectrum inversion has occurred according to the calculated correlation values. The DVB-T receiver may perform normal correlation and position inversion correlation on continual pilots using a spectrum inversion detector to automatically detect whether spectrum inversion has occurred. Related methods are also discussed.

Abstract: A method, apparatus and computer program for detecting an echo signal including interpolating at least one fast Fourier transformed OFDM signal received in the time-domain, interpolating the at least one signal generated by the time-domain interpolation in the frequency-domain, using a time-domain varying bandwidth low pass filter (LPF), with bandwidth that varies in response to a bandwidth control signal, measuring at least one signal to power ratio between a scattered pilot signal of the at least one signal generated by the time-domain interpolation and another scattered pilot signal of the at least one signal generated by the frequency-domain interpolation, and comparing the signal to power ratio to a threshold value to determine a state of an echo signal, and providing the bandwidth control signal with the determined echo state information to adjust the bandwidth of the time-domain LPF, based on the bandwidth control signal.