Abstract: A cyclic redundancy check generator for a high speed data bus is capable of outputting frames of data and cyclic redundancy check bits concatenated together without any additional space or time delay between frames while operating at a normal clock speed. Data to be transmitted is parallel loaded into series-connected registers via multiplexers connected between the registers. The multiplexers also provide parallel loading of the cyclic redundancy check bits for a frame of data from a look-ahead cyclic redundancy check logic circuit. The output of the logic circuit is also connected to a cyclic redundancy check register. The logic circuit has inputs connected to the final series-connected data register and the cyclic redundancy check register.

Abstract: A system and method for recovering a clock signal from digital data signals which do not include a separate clock signal. The system and method detect transitions from one logic state to the other logic state in the digital data signal, and compare the time alignment of these logic state transitions to an input clock signal from a voltage controlled oscillator. A correction control signal is generated as a function of the time alignment of the digital data signal transition with the input clock signal, and applied to the oscillator to vary the frequency of the clock signal as a function of the correction control signal, whereby a digital data recovered clock signal is aligned with the digital data signal.

Abstract: An arrangement for a speech enhancement processor which maintains the processed speech at a constant level regardless of large changes in the associated noise level. The composite speech and noise signal is applied to a first AGC circuit and then to a speech enhancement system which removes tonal, impulse, and wideband noises from the signal. The extracted noise power estimates are subtracted from the constant amplitude signal to provide a gain control signal value to which the gain of a second variable gain amplifier is inversely proportional. The amplifier multiplies the processed speech output from the enhancement system and, because of the variable gain control, provides an output speech signal having short-term amplitude levels which correspond to those of the input speech signal, and having a constant long-term amplitude level.