Multi-band, multi-function integrated transceiver

• US 6,448,926 B1
• Filed: 08/23/1999
• Issued: 09/10/2002
• Est. Priority Date: 11/19/1993
• Status: Expired due to Fees

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Urban, Daniel, Weinberg, Aaron, Harlacher, Marc, Bierly, Scott, Cunningham, Kenneth
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/382,202
• Time in Patent Office: 1,114 Days
• Field of Search: 342/51, 342/357.06, 342/385, 342/361, 342/362, 375/143, 375/152
• US Class Current: 342/357.73
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

A communications system operating in one or more frequency bands of various number of channels per band (for a total of N channels), and a novel transceiver for receiving these multiple bands of signals. The transceiver comprises an antenna and RF front end for each said band, a separate RF to IF downconverter for each said band. The IF for each band is centered at a succession of frequencies F_o such that the spectra for each band are non-overlapping, with the center frequencies. Analog-to-digital converter sampling rate is chosen such that one band is centered at baseband, and one or more other bands are centered at a specific relationship with the sampling rate such that each band is individually downconverted to baseband by appropriate selection of tap weight multiplying sequences (such as alternating +/− sequence for the case of F_o equal to one-fourth the sampling rate). An analog-to-digital converter converts analog signals to digital signals from the combiner. A digital downconverter converts the digital signals to baseband signals and a single digital processor sequentially time shared among all the bands and channels.

Claims

1. In a communications system receiver operating in one or more frequency bands, consisting of various number of channels per band (for a total of N channels), and for receiving said bands of signals, the improvement in said transceiver comprising:

a system of antenna and RF front end for each said band, a separate RF to IF downconverter for each said band, the IF for each band centered at a succession of frequencies F_c such that the spectra for each band are non-overlapping, with said center frequencies and a signal combiner for combining said signals, an analog-to-digital converter having an analog-to-digital converter sampling rate chosen such that one band is centered at baseband, and one or more other bands are centered at a specific relationship with the sampling rate such that each band is individually downconverted to baseband by appropriate selection of tap weight multiplying sequences,

a digital downconverter for converting said digital signals to baseband signals and a single digital processor sequentially time shared among all said Bands and channels,

a signal processor connected to said single digital processor for providing any final signal and/or data processing or formatting.

2. In a tracking and data relay satellite system operating in the S-band and in conjunction with a GPS satellite system operating in the L-band, and transceiver for receiving L-band and S-band signals, the improvement in said transceiver comprising:

a system antenna and RF front end for each said S-band and L-band signal, a separate RF to IF downconverter for each said S-band and L-band signal, said IF for said S-band signal operating at a frequency F_o and said IF signals for said L-band operating and centered at a frequency F_o plus a predetermined separation frequency so that the spectra of signals for said S-band and the spectra of signals for said L-band are non-overlapping,

a combiner for combining all said spectra of signals, an analog-to-digital converter for converting analog signals to digital signals from said combiner,

a digital downconverter for converting said digital signals to baseband signals and a single digital processor sequentially time shared among said S-band and L-band signals, respectively,

a GPS navigation processor and a S-band data processor connected to said single digital processor,

an S-band signal transmitter coupled into the said S-band transceiver antenna path.

3. A Multi-Band, Multi-Channel receiver having a Digital Matched Filter (DMF) comprising:

multiple sets (N) of PN-Generators and storage device for maintaining N sets of tap weights within the DMF,

N-stage data delay line which shifts the digital data samples down the line at the baseband sampling rate,

arithmetic circuitry for multiplying alternate taps of said delay line by one of the stored sets of tap weights, pre-multiplied by the +/−

or other appropriate downconversion sequence, and summing each of said products, to form a correlation output sample that is a member of the sequence corresponding to a channel represented by the selected tap weights;

sufficient consecutive such sum-of-products samples are thus formed to form the complete correlation epoch function corresponding to a selected channel,

whereby, during acquisition, the tap weights for a single channel are manipulated appropriately such that consecutive DMF output samples represent correlation epochs associated with a particular PN alignment (offset), and thus an acquisition detection circuit can observe which of the correlation alignments is of sufficient magnitude to indicate the correct PN alignment, and thus transition that channel into tracking,

during tracking, the tap weights are alternated between various channels and manipulated such that the output sequence from the DMF thus includes a sequence of sum-of-products samples that are in fact also a sequence of correlation epochs corresponding to each of the channels being tracked, and

during ongoing operations in fact both acquisition and tracking operations among multiple channels may be simultaneously taking place.

4. A communication receiver system for receiving multiple bands having multiple channels, at least some of said bands in said multiple bands do not spectrally overlap and said receiver including a digital down converter,

a matched filter connected to said digital down converter for multiplying alternate taps of a delay line by all of the sets of stored tap weights and summing each of a plurality of products to form a correlation output sample that is a member of a sequence corresponding to a channel represented by a selected tap weight,

a single digital processor connected to said matched filter for time sharing all said bands and channels and processing any final signal and/or data processing or formatting, and

a plurality of utilization devices connected to said single digital processor.

5. The communication receiver system defined in claim 4 wherein one of said bands is the S-band.

6. The communication receiver system defined in claim 4 wherein one of said bands is the L-band.

7. The communication receiver system defined in claim 4 wherein one of said bands is the S-band and another of said bands is the L-band.