Abstract: A receiver for burst transmission of MSK-modulated binary signals includes in-phase (I) and quadrature (Q) demodulation under the control of reference sine and cosine signals. Initially, the reference signals are near the nominal carrier frequency of the received signal, but at arbitrary phase, so that noncoherent detection takes place. A control circuit is provided to slew the reference signals to the same phase as the MSK carrier for low-noise coherent detection. Because of the burst nature of the communications, data throughput is significantly reduced if reference phase acquisition time is large. In order to reduce the phase acquisition slew time, each burst of data is preceded by a predetermined preamble. In the receiver, the noncoherently detected preamble is applied to a set of four preamble-matched correlators which respond to the I and Q portions of the preamble, and to the cross-coupled Q and I portions contaminating the I and Q portions respectively.

Abstract: A system and method for frequency division demultiplexing a received broad band signal into k.sup.m channels, each capable of containing a baseband signal component and comprising m descending tiers of identical channel division modules with the first tier thereof comprising a first module responsive to the received broad band signal to divide such broad band signal (at baseband) into k new channels each containing a baseband spectral component. Each module of each tier of modules is constructed to respond individually (by sampling and de-sampling techniques) to the spectral component in individual ones of the channels outputted from the immediately preceding higher order tier of modules to form k new additional channels each containing a baseband spectral component. Each baseband spectral component has an upper bandwidth limit which bears the same ratio to its sampling rate as the upper bandwidth limit of the originally received broad band signal bears to its sampling rate.