 Programmable down-sampler having plural decimators and modulator using same |
| The present invention discloses a programmable down-sampler, comprising (1) a first mux having a ... |
|
| Multi-carrier transmission system utilizing channels of different bandwidth |
| The present invention is a communication system for sending a sequence of symbols on a ... |
|
| Single side-band mixer |
| Applicant's invention resides, in part, in the recognition that a single sideband mixer including ... |
|
| Disc cartridge with slide shutter having catch pieces |
| The present invention has accordingly an essential object to provide an improved disc cartridge of ... |
|
| Interpolation filter selection circuit for sample rate conversion using phase quantization |
| The present invention is embodied in a filter selector for generating a filter address value to ... |
|
| Method and apparatus for controlling conveyor |
| OF THE INVENTION I. Hardware Configuration Referring now to the drawings, where like reference ... |
|
| Digital channelizer with arbitrary output sampling frequency |
| OF THE EMBODIMENTS Referring to FIG. 5, a polyphase channelizer 200 according to an embodiment of ... |
|
| Digital sample rate converters having matched group delay |
| According to a first aspect of the invention, a method is provided for operating two or more sample ... |
|
| Interpolator/decimator filter structure and a notch filter therefor |
| The present invention is intended as a solution to the problem of providing in excess of 3 dB ... |
|
|
Complementary-sequence pulse radar with matched filtering following doppler filtering
| Details |
Inventors: Urkowitz, Harry;
Assignee: General Electric Company (Moorestown, NJ)
Primary Examiner: Barron, Jr.; Gilberto
Assistant Examiner:
Attorney, Agent or Firm: Meise; William H., Young; Stephen A., Nieves; Carlos A.
A radar generates first and second mutually complementary binary code sequences. The autocorrelation functions of the first and second pulse sequences are selected so that, in the sum of their autocorrelation functions, the main lobes add, and the sidelobes are of equal amplitude and opposite polarity, and therefore cancel. The radar sequentially transmits dispersed pulses in which the chips are phase modulated with the two codes. The received pulses are applied uncompressed to the input of a Doppler filter bank, which filters them into various Doppler channels, each representative of a particular radial velocity of the target. Within each channel, the received signals modulated by the first code are matched-filtered by a filter matched to the first code, to produce a first time-compressed pulse, and those modulated by the second code are matched-filtered by a filter matched to the second code, to produce a second time compressed pulse. The time-compressed pulses include a main lobe which represents the range of the target, and also include sidelobes which may introduce range ambiguity. The first and second time compressed pulses are added together in each Doppler channel, to produce, in each channel, range pulses in which the range sidelobes are suppressed. Thus, range sidelobe suppression is accomplished without the use of discrete range sidelobe suppressors. |
|
DETAILED DESCRIPTION What is claimed is: 1.
A method for detecting anomalies, comprising the steps of: transmitting toward an anomaly a first pulse set consisting of a predetermined plurality of first pulses, said pulses of said first set being dispersed in time pursuant to a predetermined phase code; transmitting toward said anomaly a second pulse set consisting of said predetermined plurality of second pulses, said pulses of said second set being dispersed in time pursuant to a second phase code selected to be complementary to said predetermined phase code in a manner such that, after pulse compression of said first and second pulses, the resulting range sidelobes are substantially equal in amplitude and opposite in sign; receiving echoes of said first and second pulses reflected from said anomaly to produce received first and second pulse sets; Doppler filtering said received first and second pulse sets into a plurality of frequency components to produce a sequence of range values for each frequency component, each of said sequence of range values including said first and second code sequences; for each said frequency components, matched filtering each of said first and second code sequences of range values to produce first and second compressed pulses; summing said first and second compressed pulses; and after said Doppler filtering step, converting at least some of said plurality of frequency components to a common frequency.
2.
A method according to claim 1, wherein said transmitting steps each include the step of transmitting an electromagnetic pulse set.
3.
A method according to claim 1, wherein said transmitting steps are time-sequential.
4.
A method according to claim 1 wherein said step of matched filtering includes the steps of: matched filtering said first pulses; and matched filtering said second pulses following said step of matched filtering said first pulses.
5.
A method according to claim 1, wherein said step of converting at least some of said plurality of frequency components to a common frequency includes the step of converting at least some of said plurality of frequency components to a common baseband frequency
|
| Related patents |
|
|
Filtered fast Fourier transmultiplexer and method
OF A PREFERRED EMBODIMENT With reference to FIG. 2 a multi-channel digital transceiver 200 is coupled to a communication network 250. It will be appreciated that ...
|
|
|
Timing recovery system for a digital signal processor
In accordance with principles of the present invention, a timing recovery system for a digital signal receiver, receives a signal, representing successive symbols, from ...
|
|
|
Image reject mixer, circuit, and method for image rejection
According to a first aspect of the present invention there is provided an integrated image reject mixer circuit responsive to an information-bearing signal and arranged ...
|
|
|
Apparatus and method for a reduced component equalizer circuit
The aforementioned and other features are accomplished, according to the present invention, by providing an equalizer unit or adaptive filter unit in which the unit, ...
|
|
|
Multiplexed sigma-delta A/D converter
OF PREFERRED EMBODIMENTS Referring to FIG. 9A, a sigma-delta A/D converter in accordance with the invention has four sigma-delta modulators 101, 102, 103, 104 in ...
|
|
|
High order switched-capacitor filter with DAC input
The present invention disclosed and claimed herein comprises a digital-to-analog converter. The digital-to-analog converter includes a digital portion for receiving an n-...
|
|
|
Multi-stage digital to analog conversion circuit and method
The present invention is for a digital-to-analog conversion circuit (DAC) which includes an interpolation filter circuit, a noise shaper circuit, and a semi-digital FIR ...
|
|
|
Diversity receiver
It is an object of the present invention to provide a diversity receiver. The size of the receiver can be miniaturized and the cost of the receiver can be reduced ...
|
|
|
Radio receiving device for measuring an electric field level of a receiving channel and adjacent channels using common components
The present invention has been made to eliminate the above drawbacks, and has as its object to provide a radio receiving device which can measure the electric field ...
|
|
|
Dual-mode radio receiver for receiving narrowband and wideband signals
The present invention provides an improved dual-mode radio receiver operating in a radio communication system that uses either wideband or narrowband signals. The radio ...
|
|
|
Multiplexer-related 
