A digital filtering system is provided for communicating and processing signals using a digital filter for signal separation and signal enhancement. A digital correlator is provided for generating high resolution output data in response to low resolution input data processed with low resolution computational circuits. In one embodiment, a real-time time-domain correlator is provided with single-bit resolution computational elements to implement the correlation filtering operation. Use of the high speed real-time correlator of the present invention permits further enhancement of signals with the capability of compositing-after-correlation and with the capability of correlation using a plurality of correlation operators. Particular advantages are achieved with the use of the real-time correlator in a geophysical exploration system embodiment and in a communication embodiment. Systems applications of the digital filter includes a communications modem for modulating and demodulating chirp signals to enhance data communication and compositing-after-correlation in a geophysical exploration system. Detailed circuitry is provided to implement such systems including an improved chirp signal generator, a multi-chirp signal generator, a chirp modulator, and a correlation demodulator.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation in part of copending parent applications
(A) MEMORY SYSTEM USING FILTERABLE SIGNALS Ser. No. 160,872 filed on June 19, 1980; now U.S. Pat. No. 4,491,930 issued on Jan. 1, 1985;
(B) COMPUTER SYSTEM ARCHITECTURE Ser. No. 860,257 filed Dec. 14, 1977 now U.S. Pat. No. 4,371,923 issued on Feb. 1, 1983; and
(C) INTELLIGENT DISPLAY SYSTEM Ser. No. 849,733 filed Nov. 9, 1977 now abandoned;
all by Gilbert P. Hyatt; wherein said parent application Ser. No. 160,872 is a continuation in part of each application in the following chain of parent applications copending therebetween:
(1) FACTORED DATA PROCESSING SYSTEM FOR DEDICATED APPLICATIONS Ser. No. 101,881 filed on Dec. 28, 1970 proceedings therein having been terminated;
(2) CONTROL SYSTEM AND METHOD Ser. No. 134,958 filed on Apr. 19, 1971 still pending in the PTO;
(3) CONTROL APPARATUS Ser. No. 135,040 filed on Apr. 19, 1971 still pending in the PTO;
(4) APPARATUS AND METHOD FOR PRODUCING HIGH REGISTRATION PHOTO-MASKS Ser. No. 229,213 filed on Apr. 13, 1972 now U.S. Pat. No. 3,820,894 issued on June 28, 1974;
(5) MACHINE CONTROL SYSTEM OPERATING FROM REMOTE COMMANDS Ser. No. 230,872 filed on Mar. 1, 1972 and now U.S. Pat. No. 4,531,182 issued on July 23, 1985;
(6) COORDINATE ROTATION FOR MACHINE CONTROL SYSTEMS Ser. No. 232,459 filed on Mar. 7, 1972 now U.S. Pat. No. 4,370,720 issued on Jan. 25, 1983;
(7) DIGITAL FEEDBACK CONTROL SYSTEM Ser. No. 246,867 filed on Apr. 24, 1972 now U.S. Pat. No. 4,310,878 issued on Jan. 12, 1982;
(8) COMPUTERIZED SYSTEM FOR OPERATOR INTERACTION Ser. No. 288,247 filed on Sept. 11, 1972 now U.S. Pat. No. 4,121,284 issued on Oct. 17, 1978;
(9) A SYSTEM FOR INTERFACING A COMPUTER TO A MACHINE Ser. No. 291,394 filed on Sept. 22, 1972 now U.S. Pat. No. 4,396,976 issued on Aug. 2, 1983;
(10) DIGITAL ARRANGEMENT FOR PROCESSING SQUAREWAVE SIGNALS Ser. No. 302,771 filed on Nov. 1, 1972 still pending in the PTO;
(11) APPARATUS AND METHOD FOR PROVIDING INTERACTIVE AUDIO COMMUNICATION Ser. No. 325,933 filed on Jan. 22, 1973 now U.S. Pat. No. 4,016,540 issued on Apr. 5, 1977;
(12) ELECTRONIC CALCULATOR SYSTEM HAVING AUDIO MESSAGES FOR OPERATOR INTERACTION Ser. No. 325,941 filed on Jan. 22, 1973 now U.S. Pat. No. 4,060,848 issued on Nov. 29, 1977;
(13) ILLUMINATION CONTROL SYSTEM Ser. No. 366,741 filed on June 4, 1973 now U.S. Pat. No. 3,986,922 issued on Oct. 12, 1976;
(14) DIGITAL SIGNAL PROCESSOR FOR SERVO VECLOCITY CONTROL Ser. No. 339,817 filed on Mar. 9, 1973 now U.S. Pat. No. 4,034,276 issued on July 5, 1977;
(15) MONOLITHIC DATA PROCESSOR Ser. No. 402,520 filed on Oct. 1, 1973 still pending in the PTO;
(16) HOLOGRAPHIC SYSTEM FOR OBJECT LOCATION AND IDENTIFICATION Ser. No. 490,816 filed on July 22, 1974 now U.S. Pat. No. 4,029,853 issued on June 24, 1980;
(17) COMPUTERIZED MACHINE CONTROL SYSTEM Ser. No. 476,743 filed on June 5, 1974 now U.S. Pat. No. 4,364,110 issued on Dec. 14, 1982;
(18) SIGNAL PROCESSING AND MEMORY ARRANGEMENT Ser. No. 522,559 filed on Nov. 11, 1974 now U.S. Pat. No. 4,209,852 issued on June 24, 1980;
(19) METHOD AND APPARATUS FOR SIGNAL ENHANCEMENT WITH IMPROVED DIGITAL FILTERING Ser. No. 550,231 filed on Feb. 14, 1975 now U.S. Pat. No. 4,209,843 issued on June 24, 1980;
(20) ILLUMINATION SIGNAL PROCESSING SYSTEM Ser. No. 727,330 filed on Sept. 27, 1976 now abandoned;
(21) PROJECTION TELEVISION SYSTEM USING LIQUID CRYSTAL DEVICES Ser. No. 730,756 filed on Oct. 7, 1976 now abandoned;
(22) INCREMENTAL DIGITAL FILTER Ser. No. 754,660 filed on Dec. 27, 1976 now U.S. Pat. No. 4,486,850 issued on Dec. 4, 1984;
(23) MEANS AND METHOD FOR COMPUTERIZED SOUND SYNTHESIS Ser. No. 752,240 filed on Dec. 20, 1976 now abandoned;
(24) VOICE SIGNAL PROCESSING SYSTEM Ser. No. 801,879 filed on May 13, 1977 now U.S. Pat. No. 4,144,582 issued on Mar. 13, 1979;
(25) ANALOG READ ONLY MEMORY Ser. No. 812,285 filed on July 1, 1977 now U.S. Pat. No. 4,371,953 issued on Feb. 1, 1983;
(26) DATA PROCESSOR ARCHITECTURE Ser. No. 844,765 filed on Oct. 25, 1977 and now U.S. Pat. No. 4,523,290 issued on June 11, 1985;
(27) DIGITAL SOUND SYSTEM FOR CONSUMER PRODUCTS Ser. No. 849,812 filed On Nov. 9, 1977 now pending in the PTO;
(28) ELECTRO-OPTICAL ILLUMINATION CONTROL SYSTEM Ser. No. 860,278 filed on Dec. 13, 1977 now U.S. Pat. No. 4,471,385 issued on Sept. 11, 1984; and
(29) MEMORY SYSTEM HAVING SERVO COMPENSATION Ser. No. 889,301 filed on Mar. 23, 1978 now U.S. Pat. No. 4,322,819 issued on Mar. 30, 1982;
all by Gilbert P. Hyatt; where the benefit of the filing dates of all of the above-listed applications are herein claimed in accordance with the United States Code such as with 35 USC 120 and 35 USC 121;
where all of the above listed patent and patent applications are incorporated herein by reference as if fully set forth at length herein; and
where one skilled in the art will be able to combine the disclosures in said applications and patents that are incorporated by reference with the disclosure in the instant application from the disclosures therein and the disclosures herein.
A precoded waveshaping transmitter comprises a synchronous delay line circuit, a transmitter state machine and a differential current digital to analog converter. Through the provision of a plurality of precoded staggered time delayed data from the combination of the delay line circuit and transmitter state machine the DAC can provide a predetermined output. In a preferred implementation, a subharmonic frequency can be maintained at least 27dB below the fundamental frequency when the PWT is driven by an all ones Manchester encoded signal.
A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2.sup.N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.
A method for transmitting data packets having a heading followed by a data field. The data of the field is transmitted by groups of symbols. According to the OFDM technique, subcarriers modulated by the groups are generated. A frequency modulation of a carrier signal delivered by a linear ramp generator is produced with a set of modulated subcarriers. When the signal is received, mixing with a linear ramp results in subcarriers which are separated and then demodulated for supplying data. This is useful for transmitting data packets particularly in wide band networks.
Vibrational data is compressed about 8.5 to 18 times by isolating a low frequency component from the signal, frequency analyzing the signal to obtain important frequency/amplitude data, and recombining the low frequency component with the analyzed information for efficient transmission.
A method of magnetic resonance is provided that uses a frequency swept excitation wherein the acquired signal is a time domain signal is provided. In one embodiment, the method comprises, applying a sweeping frequency excitation and acquiring a time domain signal. The sweeping frequency excitation has a duration and is configured to sequentially excite isochromats having different resonant frequencies. Acquisition of the time domain signal is done during the duration of the sweeping frequency excitation. The time domain signal is based on evolution of the isochromats.
