US5263055A
Expired / Lapsed
US
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Apparatus and method for reducing harmonic interference generated by a clock signal
Assignee: Motorola Solutions Inc
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Filing: 1991-11-04
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Granted: 1993-11-16
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Expires: 2011-11-04
Abstract
Abstract An apparatus and method therefor substantially reducing the interference of a harmonic frequency component (301) of a clock signal with a filtered received signal (302), comprises a frequency spreading signal generator (127) and a signal modulator (125). The frequency spreading signal generator (127) produces a frequency spreading signal (130). The signal modulator (125) modulates the clock signal, produced by a clock signal generator (129), with the frequency spreading signal (130) to produce a modulated clock signal (131) including a modulated harmonic frequency component (303). The power level of a modulated harmonic frequency component (303), corresponding to the harmonic frequency component interfering with the filtered signal (202-204), is spread over a frequency bandwidth (f 6 -f 7 ) greater than the predetermined frequency bandwidth (f 4 -f 5 ) causing the power level of the modulated harmonic frequency component (303) within the predetermined frequency bandwidth (f 4 -f 5 ) to decrease.
Inventors
- 👤 Stephen V. Cahill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:54
CPC Classifications
H; H03; H03D; H03D1/00; H03D1/02; H03D1/04; H03B; H03B1/00; H03B1/04; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/50; H04B1/52; H03D2200/00; H03D2200/0041; H03D2200/0086
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
207 words
In a device that includes a signal generator and a filter, wherein the signal generator produces a first signal including a fundamental frequency component and harmonic frequency components having power levels, wherein the filter filters a second signal over a predetermined frequency bandwidth to produce a filtered signal, and wherein the filtered signal is susceptible to interference from at least one of the harmonic frequency components having a frequency within the predetermined frequency bandwidth, an apparatus for substantially reducing the interference of the at least one harmonic frequency component with the filtered signal, the apparatus comprising: a frequency spreading signal generator for producing a frequency spreading signal; and a signal modulator for modulating the first signal with the frequency spreading signal to produce a modulated signal including modulated harmonic frequency components, wherein the power level of at least one modulated harmonic frequency component, corresponding to the at least one harmonic frequency component interfering with the filtered signal, is spread over a frequency bandwidth greater than the predetermined frequency bandwidth causing the power level of the at least one modulated harmonic frequency component within the predetermined frequency bandwidth to decrease, whereby the interference of the at least one harmonic frequency component with the filtered signal is substantially reduced.
Claim 2
Dependent Claim
207 words
In a device that includes a signal generator and a filter, wherein the signal generator produces a first signal including a fundamental frequency component and harmonic frequency components having power levels, wherein the filter filters a second signal over a predetermined frequency bandwidth to produce a filtered signal, and wherein the filtered signal is susceptible to interference from at least one of the harmonic frequency components having a frequency within the predetermined frequency bandwidth, an apparatus for substantially reducing the interference of the at least one harmonic frequency component with the filtered signal, the apparatus comprising: a frequency spreading signal generator for producing a frequency spreading signal; and a signal modulator for modulating the first signal with the frequency spreading signal to produce a modulated signal including modulated harmonic frequency components, wherein the power level of at least one modulated harmonic frequency component, corresponding to the at least one harmonic frequency component interfering with the filtered signal, is spread over a frequency bandwidth greater than the predetermined frequency bandwidth causing the power level of the at least one modulated harmonic frequency component within the predetermined frequency bandwidth to decrease, whereby the interference of the at least one harmonic frequency component with the filtered signal is substantially reduced.
Claim 3
Dependent Claim
15 words
An apparatus in accordance with claim 1 wherein the filter further comprises a bandpass filter.
Claim 4
Dependent Claim
25 words
An apparatus in accordance with claim 1 wherein the signal generator that produces a first signal further comprises an oscillator producing a reference clock signal.
Claim 5
Dependent Claim
20 words
An apparatus in accordance with claim 1 wherein the frequency spreading signal generator further comprises a pseudorandom noise signal generator.
Claim 6
Dependent Claim
16 words
An apparatus in accordance with claim 1 wherein the signal modulator further comprises a frequency modulator.
Claim 7
Dependent Claim
16 words
An apparatus in accordance with claim 1 wherein the signal modulator further comprises a phase modulator.
Claim 8
Dependent Claim
187 words
Communication equipment including a receiver for receiving a modulated signal, comprising: a signal generator for producing a first signal including a fundamental frequency component and harmonic frequency components having power levels; a filter, in the receiver, for filtering the modulated signal over a predetermined frequency bandwidth to produce a filtered signal, wherein the filtered signal is susceptible to interference from at least one of the harmonic frequency components having a frequency within the predetermined frequency bandwidth; a frequency spreading signal generator for producing a frequency spreading signal; and a signal modulator for modulating the first signal with the frequency spreading signal to produce a modulated signal including modulated harmonic frequency components, wherein the power level of at least one modulated harmonic frequency component, corresponding to the at least one harmonic frequency component interfering with the filtered signal, is spread over a frequency bandwidth greater than the predetermined frequency bandwidth causing the power level of the at least one modulated harmonic frequency component within the predetermined frequency bandwidth to decrease, whereby the interference of the at least one harmonic frequency component with the filtered signal is substantially reduced.
Claim 9
Dependent Claim
187 words
Communication equipment including a receiver for receiving a modulated signal, comprising: a signal generator for producing a first signal including a fundamental frequency component and harmonic frequency components having power levels; a filter, in the receiver, for filtering the modulated signal over a predetermined frequency bandwidth to produce a filtered signal, wherein the filtered signal is susceptible to interference from at least one of the harmonic frequency components having a frequency within the predetermined frequency bandwidth; a frequency spreading signal generator for producing a frequency spreading signal; and a signal modulator for modulating the first signal with the frequency spreading signal to produce a modulated signal including modulated harmonic frequency components, wherein the power level of at least one modulated harmonic frequency component, corresponding to the at least one harmonic frequency component interfering with the filtered signal, is spread over a frequency bandwidth greater than the predetermined frequency bandwidth causing the power level of the at least one modulated harmonic frequency component within the predetermined frequency bandwidth to decrease, whereby the interference of the at least one harmonic frequency component with the filtered signal is substantially reduced.
Claim 10
Dependent Claim
25 words
Communication equipment in accordance with claim 7 wherein the signal generator that produces a first signal further comprises an oscillator producing a reference clock signal.
Claim 11
Dependent Claim
20 words
Communication equipment in accordance with claim 7 wherein the frequency spreading signal generator further comprises a pseudorandom noise signal generator.
Claim 12
Dependent Claim
16 words
Communication equipment in accordance with claim 7 wherein the signal modulator further comprises a frequency modulator.
Claim 13
Dependent Claim
16 words
Communication equipment in accordance with claim 7 wherein the signal modulator further comprises a phase modulator.
Claim 14
Dependent Claim
200 words
In a device that includes a signal generator and a filter, wherein the signal generator produces a first signal including a fundamental frequency component and harmonic frequency components having power levels, wherein the filter filters a second signal over a predetermined frequency bandwidth to produce a filtered signal, and wherein the filtered signal is susceptible to interference from at least one of the harmonic frequency components having a frequency within the predetermined frequency bandwidth, a method for substantially reducing the interference of the at least one harmonic frequency component with the filtered signal, the method comprising the steps of: producing a frequency spreading signal; and modulating the first signal with the frequency spreading signal to produce a modulated signal including modulated harmonic frequency components, wherein the power level of at least one modulated harmonic frequency component, corresponding to the at least one harmonic frequency component interfering with the filtered signal, is spread over a frequency bandwidth greater than the predetermined frequency bandwidth causing the power level of the at least one modulated harmonic frequency component within the predetermined frequency bandwidth to decrease, whereby the interference of the at least one harmonic frequency component with the filtered signal is substantially reduced.
Claim 15
Dependent Claim
200 words
In a device that includes a signal generator and a filter, wherein the signal generator produces a first signal including a fundamental frequency component and harmonic frequency components having power levels, wherein the filter filters a second signal over a predetermined frequency bandwidth to produce a filtered signal, and wherein the filtered signal is susceptible to interference from at least one of the harmonic frequency components having a frequency within the predetermined frequency bandwidth, a method for substantially reducing the interference of the at least one harmonic frequency component with the filtered signal, the method comprising the steps of: producing a frequency spreading signal; and modulating the first signal with the frequency spreading signal to produce a modulated signal including modulated harmonic frequency components, wherein the power level of at least one modulated harmonic frequency component, corresponding to the at least one harmonic frequency component interfering with the filtered signal, is spread over a frequency bandwidth greater than the predetermined frequency bandwidth causing the power level of the at least one modulated harmonic frequency component within the predetermined frequency bandwidth to decrease, whereby the interference of the at least one harmonic frequency component with the filtered signal is substantially reduced.
Claim 16
Dependent Claim
18 words
A method in accordance with claim 12 wherein the frequency spreading signal further comprises a pseudorandom noise signal.
Claim 17
Dependent Claim
19 words
A method in accordance with claim 12 wherein the step of modulating further comprises the step of frequency modulating.
Claim 18
Dependent Claim
19 words
A method in accordance with claim 12 wherein the step of modulating further comprises the step of phase modulating.
Claim 19
Dependent Claim
15 words
A method in accordance with claim 12 wherein the filter further comprises a bandpass filter.
Claim 20
Dependent Claim
25 words
A method in accordance with claim 12 wherein the step of producing the first signal further comprises the step of producing a reference clock signal.
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