GB1061822A - Improvements in monopulse radar receivers - Google Patents

Abstract

1,061,822. Monopulse radar. COMPAGNIE FRANCAISE THOMSON HOUSTONHOTCHKISS BRANDT. Dec. 9, 1963 [Dec. 7. 1962], No. 48506/63. Heading H4D. The invention relates to a monopulse radar, one channel, e.g. azimuth, of which is shown in Fig. 3. The signals from the two receiving antennµ 1, 2 are fed to magic T means 3 to produce sum #S and difference #D voltages. These RF signals are converted at 15 and 16 into IF voltages, to become #s and #d respectively, and are then fed to a 3db coupler 20, to produce two signals - The off boresight target deviation is proportional to /D/=/d/ or (tan #), Fig. 2 (not shown). The /#S/ /#s/ phase angle (#) between #r1 and #r2 is given by Thus, by measuring (cos #) in a demodulator 25, the output 26 can represent said target deviation. An alternative way of obtaining #r1 and #r2 is shown in Figs. 4, 5 and 6 (all not shown). Fig. 4 shows a constant impedance (R 0 ) network, When R 0 <SP>2</SP> L/C whence a signal #s at the input produces voltages across the two output resistors, equal in magnitude; but in phase quadrature. Fig. 6 shows two such networks having #s and #d as inputs, and their outputs combined by two networks as shown in Fig. 5. The final outputs #a and #b across the resistors 33 represent for phase measuring purposes, the signals #r1 and #r2. To test whether spurious differential phase shifts have been introduced, the difference signal #d is periodically suppressed, whence any output at 26 (which should be zero) is used to control a phase shifter in one of the channels to the demodulator.