Abstract: A method for automatic gain control of a front-end for a digital video receiver is provided. The method includes the following steps. First, a radio frequency signal is received and converted to an intermediate frequency signal. Then, the IF signal is amplified according to a gain. Next, the amplified IF signal is demodulated into a base-band signal, and the base-band signal is encoded into a transport stream. After that, a DC level of a pulse width modulation signal is controlled by at least one variable resistor to adjust the gain, the PWM signal being related to a setting of the gain. Afterwards, a BER measurement at each potential setting of the gain and the variable resistor under one or more power levels of the RF signal is read, and an optimum setting of the gain and the variable resistor is selected according to the BER measurements.

Abstract: This invention provides an impulsive noise suppression method in orthogonal frequency division multiplexing. The method comprises an equalization and de-mapping step for estimating a preliminary estimation of signal and a total noise estimation by utilizing ideal channel estimation, de-mapping, and pilot insertion technique on received signal; and a SNR comparison step for determining a SNR by dividing said preliminary estimation of signal and said total noise estimation and comparing said SNR with a threshold value.

Abstract: The present invention provides a method of early starting the operation of a descrambler. The method comprises the steps of receiving a, synchronous byte of a transport packet in a group of m packets, where m is an integer, generating an alignment index to indicate a location of the synchronous byte, delivering the alignment index to the descrambler, and loading an initialization sequence to the descrambler in accordance with the alignment index and starting an operation of the descrambler.

Abstract: An impulsive noise suppresser and method thereof is provided. The impulsive noise suppresser includes an automatic gain control unit, variable gain amplification unit, impulsive detection unit and impulsive suppression unit. The automatic gain control unit determines a gain value according to a PAPR. The variable gain amplification unit amplifies a reception signal by the gain value. The gain value is determined such that the amplified reception signal as unaffected by the impulsive noise can have an amplitude range smaller than a predetermined range. The impulsive detection unit is coupled to the variable gain amplification unit for determining whether the amplified reception signal is larger than a maximum value of the predetermined range and outputting an impulsive alarm signal if the reception signal is larger than the maximum value. The impulsive suppression unit suppresses the impulsive noise as receiving the impulsive alarm signal, and then outputs an output signal.

Abstract: A method of channel estimation is provided. The method is applied to a communication system having signals transmitted via a plurality of pilot and non-pilot sub-channels. The method comprises the steps of obtaining a first and second channel responses of each pilot sub-channel using pilot symbols received during a first and second time duration respectively, obtaining an estimated channel response of each pilot sub-channel by averaging the first and second channel responses thereof, and obtaining an estimated channel response of each non-pilot sub-channel by interpolation of those of the pilot sub-channels.

Abstract: A method of channel estimation used in an orthogonal frequency division multiplexing (OFDM) system. Firstly, a plurality of synchronized signals are received respectively from a plurality of sub-channels, and the channel responses of two sub-channels are known. Then, the channel responses of other channels are estimated by the statistical property derived from Jake's model according to two sub-channels whose channel responses are known.