Abstract: A data logger having a plurality of input ports has a library of predefined selectable input data conversion protocols. Inputs are individually controllable as to the type of sensor conversion. The data logging rate is varied during the recording period to ensure that all meaningful data values are recorded, while at the same time ensuring that the entire data storage capacity of the data logger will be substantially fully utilized at the completion of the recording period. Sensitivity is constantly adjusted to ensure that no meaningful data values are missed, whether the pertinent information concerns high frequency, low amplitude fluctuations (e.g., noise), or concerns longer-term trends, ignoring short-term variations.

Abstract: A spread spectrum communication system comprising a convolver to one end of which a message is fed comprising a plurality of bits, the convolver being long enough in the direction of signal propagation therethrough to store contemporaneously two message bits each of which comprises a plurality of sub-bits or chips having a predetermined sequence, signal generator means operative to generate reference bits, at one to one mark space ratio, each reference bit comprising chips or sub-bits corresponding to the reverse of the said predetermined sequence, the generator means being arranged to feed the other end of the said convolver with the reference bits so that when a reference bit travelling in one direction passes a corresponding message bit travelling in the opposite direction a `match` occurs and an output pulse is delivered from the convolver, gating means via which rectified output pulses from the convolver are fed to a clocked tapped analogue shift register or clocked tapped delay line means, a gating sign

Abstract: An improved method of spectral analysis suitable for use in microwave landing systems comprising sampling an unknown signal whereby nulls associated with a Sin x/x distribution are identified to facilitate the identification of a wanted signal.