Abstract: In response to an error signal, a pseudo-noise generator (312 or 416) generates an on-time pseudo-noise signal, an early pseudo-noise signal delayed by less than one-half of a chip interval, and a late pseudo-noise signal advanced by less than one-half of a chip interval. A correlator (302 and 304, or 404) correlates a received signal with the early and late pseudo-noise signals to generate the error signal. The combination of the pseudo-noise generator (312 or 416) and the correlator (302 and 304, or 404) creates a loop in which the on-time pseudo-noise signal tracks a received pseudo-noise code more closely than in prior art devices and enables a deinterleave and decode device (210) within the receiver to demodulate the received signal more effectively.

Abstract: A controlled receive device is disclosed having an amplifier circuit, which receives an input signal, and a control circuit which receives the input signal and outputs a controlled signal to a receiver. The receiver outputs an output signal. A controller varies the gain of the amplifier circuit in response to levels of the controlled signal and the output signal. The control circuit outputs a controlled indicator signal indicative of a level of the controlled signal and the receiver outputs an output indicator signal indicative of the output signal level. The controlled indicator signal and the output indicator signal are compared using comparators, to respective reference or threshold levels for producing control signals used by the controller for varying the amplifier gain.

Abstract: A Rake receiver having fingers is disclosed. The Rake receiver includes frequency discriminators for automatic frequency control and a combiner. Each finger includes a frequency discriminator. The combiner combines outputs from the frequency discriminators to output an average error signal which is fed back to the frequency discriminators for removing frequency offsets from all the fingers. The combiner includes an adder which adds the outputs of the frequency discriminators, and a divide circuit which divides the combined adder output by the number of the outputs which were added together to form the average error signal. The combiner further includes a filter connected between the adder and the divide circuit. In addition, further adders are provided where each of theses adders receives the average error signal and a respective one of the outputs from the frequency discriminators in order to provide an estimate of one of the frequency offsets.

Abstract: A receiver of a radio frequency signal having a pseudo-random noise (PRN) code modulated on a carrier, and techniques of processing such a signal that are especially adapted for ranging applications. Such an application is in a global positioning system (GPS or GLONASS) receiver. Both of the receiver DLL code and PLL carrier loops include a loop component that senses an error in its main loop caused by the presence of a multipath signal. The main loop is continuously adjusted by this sensed error, thereby causing the loop to track more precisely and minimize the effect of the multipath signal. The result is a more accurate range measurement.

Abstract: A pseudo-noise generator (516) generates an on-time component, an early component and a late component of a pseudo-noise code signal in response to an error signal. The on-time component is routed to a deinterleave and demodulate device (210) which demodulates and decodes baseband signals from received spread spectrum signals. An adder (518) subtracts the early component from the late component to form a summation signal. A multiplier (520) multiplies the summation with the received signal to form a product signal. An integrator (522) integrates the product signal to form the error signal. The error signal is fed back into the pseudo-noise generator (516) to fine tune the on-time component, the early component and the late component of the pseudo-noise code signal. As a result, a spread spectrum signal is demodulated and decoded using only one correlator (504) instead of two.

Abstract: A receiver of a radio frequency signal having a pseudo-random noise (PRN) code modulated on a carrier, and techniques of processing such a signal that are especially adapted for ranging applications. Such an application is in a global positioning system (GPS or GLONASS) receiver. Both of the receiver DLL code and PLL carrier loops include a loop component that senses an error in its main loop caused by the presence of a multipath signal. The main loop is continuously adjusted by this sensed error, thereby causing the loop to track more precisely and minimize the effect of the multipath signal. The result is a more accurate range measurement.