US6002925A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radio frequency transceiver and subassemblies thereof
Assignee: Symbol Technologies LLC
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Filing: 1997-03-24
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Granted: 1999-12-14
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Expires: 2017-03-24
Abstract
Abstract A transceiver having a transmitter section and a receiver section. The transmitter section includes a modulator to superimpose information, i.e., data, onto the amplitude of a suitable carrier signal, such as a microwave frequency carrier signal. The receiver section receives data carried by the carrier frequency signal and, in a heterodyning system, downconverts the received signal to a suitable intermediate frequency signal. The modulator and the downconverter are formed on a single semiconductor body, or chip of silicon. The receiver section is adapted to receive signals over a predetermined overall bandwith having frequencies within a plurality of frequency channels, each one of the channels having a predetermined channel bandwidth; and, a sampler for sampling such received signals at a sampling frequency less twice the predetermined bandwidth. The sampling frequency is selected to convert the carrier frequency of a signal within a selected one of the frequency channels to a frequency within a predetermined intermediate frequency and to convert the carrier frequencies of signals of the un-selected one of the frequency channels to frequencies above other than the predetermined intermediate frequency. The downconverted signals are converted into corresponding digital signals. A demodulator includes a Hilbert-Transform-pair filter section. The receiver includes: a first automatic gain control circuit (AGC) and is responsive to an output of the digital signal processor, for adjusting the gain of the AGC circuit in accordance with the output of the digital signal processor; and, a second AGC circuit fed by the digital signals and the output of the digital signal processor, for adjusting the gain of the magnitude of the digital signals in accordance with the output of the digital signal processor.
Inventors
- 👤 Hoai X. Vu
- 👤 Toan Vu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:07
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/027; H03K3/03; H03K3/0315; H03K3/0322; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3089; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/403; H04B1/44
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
132 words
A system, comprising: a receiving section adapted to receive signals having frequencies within a plurality of frequency channels, each one of the channels having its own predetermined channel bandwidth f b and said plurality of frequency channels extending over a predetermined overall bandwidth, and the channels having a predetermined frequency separation δ equal to or greater than twice of f b ; and a sampler for sampling said received signals at a sampling frequency less than twice the predetermined overall bandwidth, such sampling frequency being selected to convert the frequency of a signal within a selected one of the frequency channels to a predetermined intermediate frequency, f if and to convert the frequencies of signals of unselected ones of the frequency channels to frequencies other than the predetermined intermediate frequency, without overlapping.
Claim 2
Independent Claim
132 words
A system, comprising: a receiving section adapted to receive signals having frequencies within a plurality of frequency channels, each one of the channels having its own predetermined channel bandwidth f b and said plurality of frequency channels extending over a predetermined overall bandwidth, and the channels having a predetermined frequency separation δ equal to or greater than twice of f b ; and a sampler for sampling said received signals at a sampling frequency less than twice the predetermined overall bandwidth, such sampling frequency being selected to convert the frequency of a signal within a selected one of the frequency channels to a predetermined intermediate frequency, f if and to convert the frequencies of signals of unselected ones of the frequency channels to frequencies other than the predetermined intermediate frequency, without overlapping.
Claim 3
Dependent Claim
34 words
The system recited in claim 1 wherein the sampling frequency is selected to convert the frequencies of signals of unselected ones of the frequency channels to frequencies greater than f if +f b /2.
Claim 4
Dependent Claim
29 words
The system recited in claim 2 wherein the sampling frequency is selected to produce the intermediate frequency fif=δ/4, said fif being lower than converted frequencies of the unselected channels.
Claim 5
Dependent Claim
26 words
The system recited in claim 1 wherein intermediate frequency f if is determined in accordance, with the following formula: ##EQU17## where L is a non-negative integer.
Claim 6
Dependent Claim
41 words
The system recited in claim 1 wherein: ##EQU18## where f c is the carrier frequency of the selected channel, N is the number of channels, f g is a sampling frequency and K is the largest integer k satisfying k≦(4(f.sub.c /δ)-1)/4N.
Claim 7
Dependent Claim
31 words
The system recited in claim 1 wherein the receiving section included a demodulator and wherein said demodulator provides a control signal for a first AGC circuit and a second AGC circuit.
Claim 8
Independent Claim
133 words
A system comprising: a receiving section adapted to receive signals having frequencies within a plurality of frequency channels, each one of the channels having a predetermined channel bandwidth f b , and said plurality of frequency channels extending over a predetermined overall bandwidth, and the channels having a predetermined frequency separation δ equal to or greater than twice of f b ; and a sampler for sampling said received signals at a sampling frequency less than twice the predetermined overall bandwidth, the sampling frequency being selected to downconvert the frequency of a signal within a selected one of the frequency channels to a predetermined intermediate frequency f if and to convert the frequencies of signals of the unselected one of the frequency channels to frequencies other than the predetermined intermediate frequency, without overlapping.
Claim 9
Independent Claim
133 words
A system comprising: a receiving section adapted to receive signals having frequencies within a plurality of frequency channels, each one of the channels having a predetermined channel bandwidth f b , and said plurality of frequency channels extending over a predetermined overall bandwidth, and the channels having a predetermined frequency separation δ equal to or greater than twice of f b ; and a sampler for sampling said received signals at a sampling frequency less than twice the predetermined overall bandwidth, the sampling frequency being selected to downconvert the frequency of a signal within a selected one of the frequency channels to a predetermined intermediate frequency f if and to convert the frequencies of signals of the unselected one of the frequency channels to frequencies other than the predetermined intermediate frequency, without overlapping.
Claim 10
Dependent Claim
23 words
The system recite in claim 7 wherein the sampling frequency f g is selected to produce intermediate frequency f if less than δ.
Claim 11
Dependent Claim
24 words
The system recited in claim 8, wherein fif is approximately equal to (δ/4)(2L+1), where L in an integer equal to, or greater than, 0.
Claim 12
Dependent Claim
11 words
The system recited in claim 8 wherein the intermediate frequency fif=δ/4.
Claim 13
Dependent Claim
22 words
The system recited in claim 8 including a low pass filter for selectively passing only frequencies less than δ to a demodulator.
Claim 14
Dependent Claim
32 words
The system recited in claim 11 including: an analog to digital converter for converting the signals passed by the low pass filter; and a Hilbert-Transform-pair filter section for demodulating the passed signals.
Claim 15
Dependent Claim
73 words
The system recited in claim 12 wherein the Hilbert-Transform-pair section includes: a pair of filter in Hilbert-Transform-pair relationship fed by digitized, intermediate frequency signal passed by the low pass filter; a pair of multipliers fed by the outputs of the Hilbert-Transform-pair filters for producing signals representative of the square of the digitized signals fed to said multipliers; and an adder for adding the signals produced by each multiplier to generate the demodulated signal.
Claim 16
Dependent Claim
18 words
The system recited in claim 11, wherein said low pass filter passes frequencies less than ((δ/4)+(f b /2)).
Claim 17
Dependent Claim
45 words
The system recited in claim 7 wherein sampling frequency is given by: ##EQU19## where N is the number of channels, f c is a carrier frequency of the selected one of the frequency channels, f s is a sampling frequency, and K is a constant.
Claim 18
Dependent Claim
20 words
The system recited in claim 15 wherein K is the largest integer which is smaller than, or equal to: ##EQU20##
Claim 19
Dependent Claim
34 words
The system recited in claim 7 wherein the receiving section includes: a digitizer section for converting the intermediate frequency signals into corresponding digital signals; and a digital signal processor for processing the digital signals.
Claim 20
Dependent Claim
98 words
The system recited in claim 17 wherein the receiving section includes: a first automatic gain control (AGC) circuit, fed by a low pass filter passed intermediate frequency signals and responsive to an output of the digital signal processor, for adjusting the gain of the first AGC circuit in accordance with the output of the digital signal processor; and a second AGC circuit fed by the digital signals and the output of the digital signal processor, for adjusting the gain of the digital signals in the second AGC circuit in accordance with the output of the digital signal processor.
Claim 21
Dependent Claim
31 words
The system recited in claim 18 wherein the receiver section includes a demodulator and wherein said demodulator provides a control signal for the first AGC circuit and the second AGC circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-12-13 | 2003-06-14 | 2003-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-13 | 2007-06-14 | 2007-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-13 | 2011-06-14 | 2011-12-14 | $7700.00 | Window Closed / Lapsed |