Abstract: The present invention provides a method of accurately determining the signal to noise ratio (SNR) using filters. Three embodiments of the invention are disclosed: the use of fixed filters, multiple filters and dynamic filters. The total noise energy is calculated by applying low pass and high pass filters. The minimum of the two noise energies estimated by the low pass and high pass filters is selected to calculate the total noise energy in the signal. The present invention provides an accurate method of SNR estimation in conditions of low SNR and high carrier offsets, without the requirement for bringing the signal to base band. The use of multiple filters provides accurate SNR measurement even in the presence of discrete interferences.

Abstract: This invention discloses a method of accurately detecting the current bit in a SDPSK modulated signal at the receiver. The proposed method calculates the current bit from the past-detected bits and the past symbols. Each past symbol estimates the current bit. Each of these estimates is summed up to provide the final estimate of the bit. The proposed method for the reception of SDPSK modulated data improves the bit error rate performance. The proposed method can be applied in any communication system that uses SDPSK modulation.

Abstract: An RF ASIC for a subscriber communicator includes a receiver section, a transmitter section, a CODEC and an I2S port. The receiver section downconverts by superheterodyning and demodulates a received RF communication signal to provide analog quadrature components of the received signal at baseband. The transmitter section upconverts and combines analog input quadrature modulation components to provide an RF communication transmit signal and then amplifies the transmit signal for driving an external power amplifier. The CODEC processes the analog baseband quadrature components of the received signal to provide I and Q digital output signals, and processes I and Q digital input signals to provide the analog input quadrature modulation components for said upconversion. The I2S port combines the I and Q digital output signals for output as a serial digital signal stream, and separates the I and Q digital input signals from an input serial digital signal stream.