Single-sideband (SSB) and AM signals are analyzed using a waveform that can be varied in shape from a spike through a sine wave to a square wave by varying a parameter. The average sideband powers and the peak envelope powers are then calculated and compared. It is shown that the ratio of average sideband power to peak envelope power for AM is more favorable than that for SSB for 'squarish' modulating signals. However, the ratio for SSB is about 9 dB higher than it is for AM for modulating signals ranging in shape from a sine wave to a spike.>

The input signal is assumed to be simultaneously amplitude and phase modulated (AM and PM), and the bandpass filter may be unsymmetrical and mistuned. The demodulator output is the magnitude of the filtered signal for an AM receiver or its phase for a PM receiver. For such a system with amplitude demodulation, the results are found and presented in the form of an expansion in which the leading term is the linear (i.e., undistorted) reproduction of the input AM and the successive terms represent the distortion and crossmodulation. The significant effects are given by the first few terms of the expansion because the applications of interest are those in which the distortion is small. A spectral analysis is performed on the output of an AM receiver. The leading DC, linear, and nonlinear terms of the output power spectrum are derived by assuming that the amplitude- and phase-modulating signals are uncorrelated zero-mean random Gaussian processes.>

A new algorithm for routing data packets in networks of computers connected by communication links is given by Chyung and Reddy. Because they assume that the communication links are two-way, their result applies, properly, to routing messages in a graph. However, some communication networks have asymmetrical cross links either by design or because the radio circuits that must be paralleled in opposite directions to compose them may fail. Such networks are represented by digraphs and it is clear that they require a generalized routing algorith. A simple modification of Chyung and Reddy's routing algorithm, shown below, provides this generalization.

A modified form of pulse-code modulation, called weighted pcm, is described in which the relative amplitudes of the pulses within the pulse-code groups are adjusted so as to minimize the noise power in the reconstructed signal due to errors in transmission. A performance analysis shows the knee of the output signal-to-noise ratio curve to be moved 1.4 db to the left for a weighted seven-digit pcm system. An information rate study reveals that the maximum improvement which can ever be achieved by any encoding process over a conventional seven-digit pcm system is only 8 db. The importance of selecting a suitable system worth criterion is emphasized by showing that weighting increases the information rate relative to an rms fidelity criterion but decreases it on a pure equivocation basis.