Beam-forming reconfigurable correlator (pulse compression receiver) based on multi-gigabit serial transceivers (SERDES)
Aspects of the invention provide improvements to electromagnetic and other wave-based ranging systems, e.g., RADAR or LIDAR systems, of the type having transmit logic that transmits a pulse based on an applied analog signal. The improvements are characterized, in part, by a SERDES having a serializer (a/k/a a “transmit side”) that is coupled to the transmit logic. The serializer has (i) an input to which a pattern on which the pulse is based is applied and (ii) an output from which a serialization of the pattern is applied to the transmit logic. The improvements are further characterized in that the SERDES has deserializer logic (a/k/a a “receive side”) that is coupled to receive logic and that deserialize a received “analog” signal containing possible reflections of the pulse. According to various aspects of the invention, the transmit and/or receive logic can include circuitry for directionally steering pulses transmitted into the environment and/or the directional sensitivity of the system to possible reflects of those pulses.
1. In an electromagnetic ranging system of the type that transmits pulses into an environment, the improvement comprising
A. a serializer/deserializer (“SERDES”) having a serializer with (i) an input to which a pattern is applied and (ii) an output on which pulses representing a serialization of the pattern are generated,
B. transmit logic that is coupled to the output of the serializer of the SERDES and that transmits the pulses into the environment,
C. the transmit logic including a bootlace lens that directionally steers the pulses transmitted into the environment.
2. In the system of claim 1 , the further improvement wherein the bootlace lens is a Rotman lens.
3. In the system of claim 2 , the further improvement wherein the Rotman lens has an input that is coupled to receive by way of a switch the pulses generated by the serializer.
4. In the system of claim 3 , the further improvement wherein an input of the switch receives the pulses generated by serializer, following any of amplification and conditioning.
5. In the system of claim 3 , the further improvement wherein the switch has multiple selectable outputs, each coupled to a corresponding beam port of the Rotman lens.
6. In the system of claim 3 , the further improvement wherein the Rotman lens has a plurality of element ports, each of which is coupled to a transmit antenna.
7. In the system of claim 6 , the further improvement wherein the switch selectively routes a radio frequency (RF) signal generated from pulses generated by serializer, following any of amplification and conditioning, for application to one or more of the beam ports of the Rotman lens.
8. In the system of claim 7 , the further improvement wherein an array comprising plural ones of the transmit antennas radiates the RF signal in a direction determined by the one or more ports of Rotman lens to which the RF signal is applied.
9. In the system of claim 6 , the further improvement wherein the switch selectively routes radio frequency (RF) signal generated from the pulses generated by serializer, following any of amplification and conditioning, for application to two beam ports of the Rotman lens.
10. In the system of claim 9 , the further improvement comprising circuitry interposed between each output of the switch and each corresponding beam port of the Rotman lens, where that circuitry varies a phase of the signals transferred therebetween.
11. In a ranging system of the type that transmits a pulse into the environment, the improvement comprising
A. transmit logic that transmits a plurality of pulses into the environment based on an applied signal, the applied signal comprising a signal that is applied to the transmit logic,
B. a plurality of receiver sections, each that has receive logic that receives from the environment an analog signal that is a possible reflection of the plurality of pulses, each receiver section further comprising
(i) a serializer/deserializer (“SERDES”) having a deserializer that is coupled to the receive logic of that section and that generates a stream of digital samples of the analog signal received by that receive logic,
(ii) a correlator that correlates that stream against a pattern on which the transmitted plurality of pulses is based.
12. In the ranging system of claim 11 , the further improvement comprising range-finding logic that is coupled to the correlators of the plurality of receiver sections.
13. In the ranging system of claim 12 , the further improvement wherein the range-finding logic determines any of a distance, velocity, bearing, doppler, and/or absolute or relative position of an object from which a said plurality of pulses transmitted by the transmit logic and received by the receiver sections is reflected.
14. In the ranging system of claim 11 , the further improvement in which each deserializer samples the applied analog signal at a rate of at least 3 gigasamples per second (GSPS).
15. In the ranging system of claim 11 , the further improvement in which each deserializer samples the applied analog signal at a rate of at least 28 gigasamples per second (GSPS).
16. In the ranging system of claim 11 , the further improvement in which the SERDES is implemented in any of a ASIC and an FPGA.
17. In the ranging system of claim 11 , the further improvement
wherein each correlator comprises a plurality of multiply-and-accumulate (MAC) units, each coupled to receive a respective portion of the digital stream from the deserializer of the respective receiver section,
where each portion of the digital stream comprises a plurality of successive or substantially successive samples of the analog signal received by that receiver section, and
where each portion of the digital stream includes at least one sample not in the other portions.
18. In the ranging system of claim 17 , the further improvement wherein where each MAC (i) multiplies its respective portion with of the digital stream, on a bit-by-bit basis, with the signal pattern and (ii) sums results of those multiplications over a plurality of bits that make up that respective portion.
19. In the ranging system of claim 11 , the further improvement wherein the transmit logic comprises
A. a SERDES having a serializer with (i) an input to which a pattern is applied and (ii) an output that is coupled to the transmit logic and on which a serialization of the pattern is generated as the applied signal, and
B. a bootlace lens.
20. A ranging system comprising
A. one or more serializer/deserializer's (“SERDES's”), each having a serializer with (i) an input to which a pattern is applied and (ii) an output on which pulses representing a serialization of the pattern are generated,
B. a plurality of transmit antennas that together transmit said pulses into the environment,
C. transmit logic that is coupled between the one or more SERDES's and the plurality of transmit antennas to directionally steer the pulses transmitted by those transmit antennas into the environment.