AN ANALYSIS OF TRANSMITTED SIGNAL DISTORTION RESULTING FROM ANTENNA TO REFLECTING SURFACE VELOCITY.
Technical rept. Sep 66-Feb 67,
AIR FORCE WEAPONS LAB KIRTLAND AFB NM
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Distortion of transmitted signals caused by Doppler frequency spreading and amplitude modulation is a consequence of the relative velocity between the transmitter and a reflecting surface. General equations yielding velocity components to any point in the illuminated area on the surface, received power as a function of time, and generalized effects of vehicle motion on the transmitted frequency spectrum are derived. The Fourier spectrum of the range modulation function is calculated using computer techniques. With this, the spectral spreading of the transmitted signal due to rate of change of range is obtained. A specific transmitting-receiving system is analyzed. The system transmits a frequency-modulated continuous-wave FM-CW signal. The receiver consists of a balanced mixer, a band-pass filter, a square-law device, and a low-pass filter. The analysis of the system begins with the signal received from a single point reflector and is extended to signals received from many points simultaneously. This particular system is selected because it allows a unique analysis, in that the functional design would be dependent on the amount of signal distortion as defined in this research. A summary of the analysis is given, together with recommendations of topics for further study in the area of analysis of signals returned from various terrains. Author
- Active and Passive Radar Detection and Equipment
- Radiofrequency Wave Propagation