Abstract: A system and method for providing optimum wireless communication spreading code selection such that communication channel interpath interference is minimized. In Direct-Sequence Spread-Spectrum, the autocorrelation properties of a spreading code greatly affects the inherent ability of a system to resist multipath. Low/spreading gain codes (or “short” codes) associated with high data rates do not perform well where large-amplitude multipath is present. The system and method presented herein overcomes this problem by selecting spreading codes in such a way that interference caused by multipath is minimized. The system and method does so by determining the characteristics of the radio-frequency link in order to select a spreading code that will minimize interpath interference.

Abstract: A discrete multi-tone (DMT) processor receives predetermined control signals from a digital signal processor (DSP) within an asymmetric digital subscriber line (ADSL) modem, modulates transmission data in response to the control signals, and demodulates reception data. The DMT processor includes a frame synchronization signal generator, a transmitter, and a receiver. The frame synchronization generator generates a transmission frame synchronization signal and a reception frame synchronization signal in response to a cyclic prefix contained in the transmission data or reception data and a reception synchronization shift signal applied from the DSP. The transmitter DMT modulates and gain-controls the transmission data input in response to the transmission frame synchronization signal The receiver gain-controls and DMT demodulates the reception data response to the reception frame synchronization.

Abstract: A receiver which may be an xDSL receiver has improved dynamic range. The receiver has a first amplifier, a network of four impedances and a variable gain second amplifier. The variable gain second amplifier has an input connected to an ouput of the first amplifier, an output connected to the first amplifier, and a variable gain control input. The gain of the variable gain second amplifier is 1 K , and the pass-band gain of the receiver is K. By controlling the gain of the receiver with an AGC (automatic gain control), the receiver can amplify and filter inputs over a wide dynamic range with lower distortion and without saturation. Alternatively, the gain of the variable gain second amplifier is - 1 K . The four impedances can be arranged to realise low-pass or high-pass filters.

Abstract: A BTSC-compatible encoder that is integrated onto an application specific integrated circuit includes a low pass filter that is responsive to a digital representation of an audio signal that has a sample rate of FS. The low pass filter generates a corresponding second digital signal having an pseudo-interpolated sampling rate of 4FS. A digital infinite impulse response pre-emphasis filter generates a pre-emphasized output signal corresponding to the second digital signal. A digital signal compressor that is responsive to the pre-emphasized output signal, generates a compressed digital signal corresponding to the pre-emphasized output signal. A digital phase locked loop that is responsive to a video sync pulse having a sync pulse frequency, generates a third digital signal corresponding to a sinusoid having a frequency equal to twice the sync pulse frequency and a having a sampling frequency equal to 4FS.