Abstract: A multi-carrier receiver system and method for receiving a transmission frequency multi-carrier signal include a feedforward cancellation loop. A frequency conversion circuit generates an intermediate frequency (IF) multi-carrier signal based on the transmission frequency multi-carrier signal. The feedforward cancellation loop generates an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal. A primary A/D converter having a significantly lower dynamic range requirements can therefore generate a digital multi-carrier signal based on the amplitude corrected multi-carrier signal. The feedforward cancellation loop therefore enables the primary A/D converter to process multi-carrier signals without the need for large dynamic range requirements.

Abstract: A multi-carrier receiver system and method for receiving a transmission frequency multi-carrier signal include a feedforward cancellation loop. A frequency conversion circuit generates an intermediate frequency (IF) multi-carrier signal based on the transmission frequency multi-carrier signal. The feedforward cancellation loop generates an amplitude corrected multi-carrier signal based on the IF multi-carrier signal such that the amplitude corrected multi-carrier signal has a reduced dynamic range with respect to the IF multi-carrier signal. A primary A/D converter having a significantly lower dynamic range requirements can therefore generate a digital multi-carrier signal based on the amplitude corrected multi-carrier signal. The feedforward cancellation loop therefore enables the primary A/D converter to process multi-carrier signals without the need for large dynamic range requirements.

Abstract: In an RF receiver a system is provided to digitally determine when a pulse has stabilized and when a pulse has restabilized after becoming unstable. The restabilized levels can be detected whether they are above or below the initial stabilization level. The system uses the stable information to determine if a pulse-on-pulse signal is being received or if a trailing edge pulse is being received. The system can provide separate information about each pulse in a pulse-on-pulse situation and can provide separate information concerning the leading pulse and trailing pulse when the trailing pulse occurs in the shadow of the leading pulse.

Abstract: A channelized receiver having multiple sectors wherein each antenna of said receiver system is electronically connectable to any combination of sectors to improve the flexibility of said receiver. The bandwidth of each sector is electronically selectable adding further flexibility to the receiver mission. The signal characteristics of time of arrival, pulse amplitude and time of departure are processed digitally in real time and false pulses are eliminated through arbitration in real time. Remaining pulse calculations such as angle of arrival, frequency, pulse width and pulse repetition interval and environment filtering are not calculated in real time.

Abstract: A method and apparatus for processing the log video output of a receiver that can measure multiple time overlapped pulses on a nearly instantaneous basis. The receiver measures frequency, pulse modulation, time of arrival, amplitude, pulse width and phase difference when simultaneous pulses are present. To detect pulse parameters a given voltage threshold must be exceeded and M out of the last N data samples must fall within a given voltage window that is above the threshold voltage. Pulse detection is initiated by establishing a dynamic noise threshold that is above the random noise level. When a pulse arrives, the value of the amplitude samples are measured and when the successive differences between the amplitude samples are small enough then a pulse presence is declared. Following detection of a pulse, amplitude samples are continuously taken and processed to detect the end of the pulse or a pulse-on-pulse condition.

Abstract: Acoustic wave devices employing shallow bulk acoustic waves rather than surface acoustic waves, to provide higher frequencies of operation and other significant advantages, such as less susceptibility to aging and less sensitivity to surface contamination. In each embodiment of the invention, a transmitting transducer and a receiving transducer are oriented on the surface of an anisotropic piezoelectric crystal to achieve substantial coupling of shallow bulk acoustic waves and essentially zero coupling of surface acoustic waves. In one embodiment of the invention, various types of grating filters utilize shallow bulk acoustic waves, and a set of parallel mechanical or electrical discontinuities at or near the surface of the crystal provide reflection of acoustic energy at a frequency determined by the spacing of the discontinuities. Uniformly spaced gratings provide bandpass filter operation, and gratings with graduated spacings provide for frequency compression or expansion.