Patent GB-582403-A (GB)
Title: Improvements in electrical range-finding apparatus
IPC: G01S1/02
Filed: 1940-05-28
Abstract: 582,403. Radiolocation. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., KEMP, R. J., and FEWINGS, D. J. May 28, 1940, No. 9371. [Class 40 (v)] [Also in Group XXXVI] In a range-finder of the radio reflection type in which transmitted and reflected impulses effect momentary departures from the normal movement of an indicator such as a cathode ray, the range of the scale is increased by causing the moving ray to make between successive transmissions several excursions along the time base, displaced'from one another in a direction perpendicular to the time base. A crystal controlled master oscillator A operating at about 100 kc. per sec. controls a sine wave oscillator B of the dynatron type which operates as a frequency divider and may run at a third of the frequency of the master oscillator. The output of the frequency divider B is applied to the rectangular wave form generator C, the output of which is applied to a sawtooth wave generator D so arranged that the rising and falling sides of the saw-tooth wave are of equal slope. The output of the generator D is applied to a paraphase voltage-amplifier E so as to produce two saw-tooth wave-forms having sides of equal slope, but one being phase displaced by 180 degrees relatively to the other. The output of this paraphase amplifier is applied to one pair of plates X of a cathoderay indicator. The output from the frequency divider B is also applied to a phase-adjusting valve circuit F, output from which is applied to a counter frequency divider G. Output from this consists of a positive pulse followed by a negative excursion, the pulses being spaced apart, and is applied to a second saw-tooth wave generator H which generates a saw-tooth wave having a slowly rising face and a rapidly falling face. Output from this is applied to a second paraphase voltage amplifier I which produces two outputs each similar to the input, but phase displaced by 180 degrees. These outputs are applied to the other pair Y of plates of the cathode-ray tube. The phaseadjusting valve circuit F synchronizes the beginning of the component of movement of the luminous spot in the direction perpendicular to the traverse with the beginning of one of the traverses of the cathode ray along the time base. The transmission pulse is derived from a multi-vibrator J driven by the master oscillator, the time constants of the circuits being chosen to produce a pulse of about one-thirtieth of the interval between the pulses. The output from the master oscillator A is applied through a second phase adjusting valve circuit M to the multi-vibrator J, the output of which consists of a positive pulse followed by a negative excursion, the pulses being spaced apart. This output and the output from the paraphase voltage amplifier I are applied to a mixer K, which consists of two valves having a common load resistance in the cathode lead. The mixed signal is applied to a pulse separator and amplifier L, N giving a short positive pulse for modifying the transmitter. The pulse may be adjusted by means of the phase adjusting valve circuit M.