A Time-Sampling and Amplitude-Quantizing Tube

The possibility of a saving of bandwidth- or of transmitting additional information in a given bandwidth-by means of amplitude quantizing and time sampling is reviewed. The requirements on a tube to simultaneously time sample and quantize a video input, and to produce a residue output, are outlined. Beam deflection-type tubes were successfully built and tested which perform all of these functions. They will change a continuous signal into a quantized signal having six discrete amplitude levels. The signal may also be simultaneously sampled as often as ten million times per second. A residue signal is also generated. The tube response is sufficiently accurate to meet the requirements of the system outlined. The stability of operation is such that after initial setup no critical operating conditions or adjustments are involved. Two types of output structure have been used, both of which permit the external adjustment of the output amplitude levels. The tube operates with an anode voltage of 300 volts. While the maximum operating beam current is only 55 microamperes, the signal-to-noise ratio of the tube is computed to be 55 db.