| 摘要 |
PURPOSE:To obtain a low noise demodulator simple employing an analog system by detecting an input signal synchronizing a signal as product of two reference signals which are the half of the sum of angular frequencies of two rotating shafts and the half of the difference therebetween respectively. CONSTITUTION:An input signal 30 is modulated with a rosette scan antenna 31 and brought down to an intermediate frequency with a local oscillator 36 and a mixer 32 to obtain a video signal 71 through an amplitude detector 34. On the other hand, reference signals 41 and 42 are inputted into a multiplier 87 from two rotating shafts of the antenna 31 and applied with 1/2 dividers 88 and 89 to obtain signals 90 and 91 equivalent to the half of the sum of two angular frequencies and the difference therebetween respectively. The video signal 71 is detected synchronizing a signal as product of the signals 90 and 91 and the product of a signal obtained by shifting the signal 91 by pi/2 in the phase and the signal 90 to obtain an error signal 25 in the azimuth and an error signal 26 in the elevation. |
