Coherent Square Wave Demodulation of Ideal Limiter Output

An ideal limiter may be used to single-bit quantize a noisy sinusoidal signal. This digitization is particularly economical if the signal is to be recorded. lt might then be desired to obtain phase coherence with the limited input signal. A single-bit digital phase-locked loop. utilizing a square wave reference, could be used for this purpose. The effects of coherent square wave demodulation on the signal-to-noise ratio and the (signal-to-noise spectral density) ratio are discussed. The latter result is directly applicable to the performance of the digital phase-locked loop.     

Convergence Rate of the Extended SMI Algorithm for Narrowband Adaptive Arrays

An extended sample matrix inversion (SMI) algorithm can be used for minimizing the mse (mean-squared error) between the output of an N-element adaptive array and a desired reference signal. This algorithm is shown to yield mse within 3 dB of minimum (on the average) after (2N - 1) observations of the antenna element outputs.     

Controlling Adaptive Antenna Arrays with the Sample Matrix Inversion Algorithm

Considerations are given leading to the selection of the samplematrix inversion algorithm for the control of an airborne narrowbandand adaptive receiving array for use in omnidirecti com communications. Performance is measured for a laboratory nulling system which implements this design concept. This performance ance is compared with predictions based on the component tolerances of the laboratory system.     

Integrated micro-electro-mechanical sensor development for inertialapplications

Electronic sensing circuitry and micro-electro-mechanical sense elements can be integrated to produce inertial instruments for applications unheard of a few years ago. This paper describes the Sandia M³EMS fabrication process, inertial instruments that have been fabricated, and the results of initial characterization tests of micro-machined accelerometers     

Adaptive Main-Beam Nulling for Narrow-Beam Antenna Arrays

Narrow-beam, low-sidelobe antennas may be used to enhance communication in the presence of sidelobe interferers. Protection against main-beam interferers as well can be obtained through the use of an adaptive multibeam antenna. Such an antenna, suitable for time-multiplexed, multichannel signals is described here. The objective is to permit successful communication and signal direction-of-arrival tracking in the presence of a large number of sidelobe interferers and a small number of main-beam interferers.