US5907254A
Expired / Lapsed
US
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Reshaping periodic waveforms to a selected duty cycle
Assignee: Circuit Integration Tech Inc
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Filing: 1996-02-05
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Granted: 1999-05-25
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Expires: 2016-02-05
Abstract
Abstract The invention provides a method and system for reshaping periodic waveforms to a selected duty cycle. An incoming periodic waveform has its edge transitions stretched out, and the stretched edge transitions compared with an adaptively selected threshold, to generate a reshaped waveform with a 50% duty cycle. The incoming periodic waveform is a square wave clock signal. The edge transitions are stretched using an inverter which is biased and filtered, and the stretched edge transitions are squared off using a comparator. The reference voltage for the comparator is selected using a second filter coupled in a feedback configuration with the biasing transistors for the inverter.
Inventors
- 👤 Theodore H. Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:55
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/156; H03K5/1565; H03K5/01; H03K5/08; H03K5/082; H03K5/086
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
105 words
A system for reshaping periodic waveforms to a selected duty cycle, said system comprising means for receiving an incoming waveform, said incoming waveform having a set of edge transitions; means for stretching said edge transitions to produce a set of stretched edge transitions; means for comparing said stretched edge transitions with a variable threshold, whereby said means for comparing generates a reshaped waveform with a duty cycle exactly equal to a selected value; and wherein said means for comparing comprises an input coupled to the variable threshold, said variable threshold being selected using a filter coupled in a feedback configuration with said means for stretching.
Claim 2
Independent Claim
105 words
A system for reshaping periodic waveforms to a selected duty cycle, said system comprising means for receiving an incoming waveform, said incoming waveform having a set of edge transitions; means for stretching said edge transitions to produce a set of stretched edge transitions; means for comparing said stretched edge transitions with a variable threshold, whereby said means for comparing generates a reshaped waveform with a duty cycle exactly equal to a selected value; and wherein said means for comparing comprises an input coupled to the variable threshold, said variable threshold being selected using a filter coupled in a feedback configuration with said means for stretching.
Claim 3
Dependent Claim
16 words
A system as in claim 1, wherein said incoming waveform comprises a square wave clock signal.
Claim 4
Dependent Claim
14 words
A system as in claim 1, wherein said means for stretching comprises a filter.
Claim 5
Dependent Claim
14 words
A system as in claim 1, wherein said means for stretching comprises an inverter.
Claim 6
Dependent Claim
16 words
A system as in claim 4, wherein said inverter in said means for stretching is biased.
Claim 7
Independent Claim
130 words
A system for reshaping periodic waveforms to a selected duty cycle, said system comprising means for receiving an incoming waveform, said incoming waveform having a set of edge transitions; means for stretching said edge transitions to produce a set of stretched edge transitions; means for comparing said stretched edge transitions with a variable threshold, whereby said means for comparing generates a reshaped waveform with a duty cycle exactly equal to a selected value; and wherein said means for stretching comprises an inverter coupled to means for biasing said inverter; said means for receiving is coupled to an input for said inverter; said inverter is coupled to a first filter; said means for comparing is coupled to a second filter; and said second filter is coupled to said means for biasing.
Claim 8
Independent Claim
130 words
A system for reshaping periodic waveforms to a selected duty cycle, said system comprising means for receiving an incoming waveform, said incoming waveform having a set of edge transitions; means for stretching said edge transitions to produce a set of stretched edge transitions; means for comparing said stretched edge transitions with a variable threshold, whereby said means for comparing generates a reshaped waveform with a duty cycle exactly equal to a selected value; and wherein said means for stretching comprises an inverter coupled to means for biasing said inverter; said means for receiving is coupled to an input for said inverter; said inverter is coupled to a first filter; said means for comparing is coupled to a second filter; and said second filter is coupled to said means for biasing.
Claim 9
Independent Claim
158 words
A system for re-shaping periodic waveforms to a selected duty cycle, said system comprising means for receiving an incoming waveform, said incoming waveform having a set of edge transitions, said means for receiving is coupled to a gate node for said second and a gate node for said third transistor; means for stretching said edge transitions to produce a set of stretched edge transitions, said means for stretching comprises first, second, third and fourth transistors coupled between a voltage source and a voltage drain; means for comparing said stretched edge transitions with a variable threshold responsive to said incoming waveform, whereby said means for comparing generates a reshaped waveform with a duty cycle exactly equal to a selected value, and wherein said variable threshold is substantially DC in nature, said means for comparing is coupled to said comparator; and said comparator is coupled to a gate node for said first and a gate node for said fourth transistor.
Claim 10
Independent Claim
158 words
A system for re-shaping periodic waveforms to a selected duty cycle, said system comprising means for receiving an incoming waveform, said incoming waveform having a set of edge transitions, said means for receiving is coupled to a gate node for said second and a gate node for said third transistor; means for stretching said edge transitions to produce a set of stretched edge transitions, said means for stretching comprises first, second, third and fourth transistors coupled between a voltage source and a voltage drain; means for comparing said stretched edge transitions with a variable threshold responsive to said incoming waveform, whereby said means for comparing generates a reshaped waveform with a duty cycle exactly equal to a selected value, and wherein said variable threshold is substantially DC in nature, said means for comparing is coupled to said comparator; and said comparator is coupled to a gate node for said first and a gate node for said fourth transistor.
Claim 11
Dependent Claim
18 words
A system as in claim 1, comprising means for comparing said reshaped waveform with a selected threshold voltage.
Claim 12
Dependent Claim
13 words
A system as in claim 1, comprising means for selecting said variable threshold.
Claim 13
Dependent Claim
14 words
A system as in claim 9, wherein said means for selecting comprises a filter.
Claim 14
Dependent Claim
36 words
A system as in claim 9, wherein said means for selecting comprises a biasing circuit, whereby said means for selecting selects said variable threshold in response to a duty cycle ratio selected by said biasing circuit.
Claim 15
Dependent Claim
15 words
A system as in claim 1, wherein said selected value is a 50% duty cycle.
Claim 16
Independent Claim
69 words
A system for reshaping waveforms to a selected duty cycle, said system comprising a biased inverter having an input having means for receiving an incoming waveform; a filter coupled to an output of said biased inverter; a comparator coupled to an output of said filter; and a biasing circuit coupled to an output of said comparator and coupled to both an input of said comparator and said biased inverter.
Claim 17
Independent Claim
69 words
A system for reshaping waveforms to a selected duty cycle, said system comprising a biased inverter having an input having means for receiving an incoming waveform; a filter coupled to an output of said biased inverter; a comparator coupled to an output of said filter; and a biasing circuit coupled to an output of said comparator and coupled to both an input of said comparator and said biased inverter.
Claim 18
Independent Claim
100 words
A system for reshaping waveforms to a selected duty cycle comprising a biased inverter having an input having means for receiving an incoming waveform; a filter coupled to an output of said biased inverter; a first comparator coupled to an output of said filter; a second comparator coupled to an output of said first comparator, said second comparator having an input coupled to a threshold voltage; and a biasing circuit, an input of which coupled to an output of said second comparator, an output of which is coupled to both an input of said first comparator and said biased inverter.
Claim 19
Independent Claim
100 words
A system for reshaping waveforms to a selected duty cycle comprising a biased inverter having an input having means for receiving an incoming waveform; a filter coupled to an output of said biased inverter; a first comparator coupled to an output of said filter; a second comparator coupled to an output of said first comparator, said second comparator having an input coupled to a threshold voltage; and a biasing circuit, an input of which coupled to an output of said second comparator, an output of which is coupled to both an input of said first comparator and said biased inverter.
Claim 20
Dependent Claim
27 words
A system as in claim 13, comprising a filter coupled to an output of said comparator, an output of said filter being coupled to said biasing circuit.
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| 3.5 Years (Year 4) | 2002-05-24 | 2002-11-23 | 2003-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-24 | 2006-11-23 | 2007-05-25 | $3760.00 | Window Closed / Lapsed |
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