US5576652A
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Digital phase shifter
Assignee: Tektronix Inc
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Filing: 1995-10-18
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Granted: 1996-11-19
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Expires: 2015-10-18
Abstract
Abstract A digital phase shifter produces from an input clock signal quadrature pairs of the input clock signal. The quadrature pairs are mixed and summed in response to a desired phase angle control signal to produce a phase shifted clock signal. The quadrature pairs are produced from a counter having as input a signal at four times the input clock signal frequency, with one output being a signal at the input clock signal frequency. The clock output signal is delayed one-quarter of a cycle to form a quadrature clock output signal, and the in-phase and quadrature clock output signals are converted to complementary quadrature signals. The complementary quadrature signals are input to a double 4:1 multiplexer so as to produce for any selection signal a quadrature pair of signals at the output defining one of four quadrants. The selected quadrature pair is mixed in a 2:1 multiplexer by a selection signal that alternates between states as a function of the comparison between the most significant bits from the counter and a fine angle control signal. The output from the multiplexer is bandpass filtered at the input clock frequency to produce the phase shifted clock signal.
Inventors
- 👤 Kenneth A. Boehlke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:23
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/08; H03K; H03K5/00; H03K5/13; H03K5/131
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
92 words
A digital phase shifter comprising: means for digitally generating from an input clock signal two sets of complementary clock signals, the clock signals of one set being in quadrature with the clock signals of the other set; and means, having the two sets of complementary clock signals input as quadrature pairs, for mixing the clock signals of a selected one of the quadrature pairs as a function of a desired phase shift to produce a phase shifted clock signal representing the input clock signal shifted in phase by the desired phase shift.
Claim 2
Dependent Claim
92 words
A digital phase shifter comprising: means for digitally generating from an input clock signal two sets of complementary clock signals, the clock signals of one set being in quadrature with the clock signals of the other set; and means, having the two sets of complementary clock signals input as quadrature pairs, for mixing the clock signals of a selected one of the quadrature pairs as a function of a desired phase shift to produce a phase shifted clock signal representing the input clock signal shifted in phase by the desired phase shift.
Claim 3
Dependent Claim
47 words
The digital phase shifter as recited in claim 1 wherein the digitally generating means comprises: means for multiplying the frequency of the input clock signal to produce a multiple-times clock signal; and means for producing from the multiple-times clock signal the two sets of complementary clock signals.
Claim 4
Dependent Claim
82 words
The digital phase shifter as recited in claim 2 wherein the producing means comprises: means for cyclically counting cycles of the multiple-times clock signal, the counting means having N outputs, one output of which provides a one-times clock signal at the frequency of the input clock signal; means for deriving from the one-times clock signal a quadrature one-times clock signal; and means for generating from the one-times clock signal and the quadrature one-times clock signal the two sets of complementary clock signals.
Claim 5
Dependent Claim
35 words
The digital phase shifter as recited in claim 3 wherein the generating means comprises means for converting the one-times clock signal and the quadrature one-times clock signal into the two sets of complementary clock signals.
Claim 6
Dependent Claim
92 words
The digital phase shifter as recited in claim 3 wherein the mixing means comprises: means for selecting from the input quadrature pairs in response to a coarse angle control signal the clock signals of the selected one of the quadrature pairs representing a selected quadrant of phase angles; and means for alternatingly selecting between the clock signals of the selected one of the quadrature pairs in response to a fine angle control signal to produce the phase shifted clock signal, the coarse and fine angle control signals representing the desired phase shift.
Claim 7
Dependent Claim
71 words
The digital phase shifter as recited in claim 5 wherein the alternatingly selecting means comprises: means for comparing the outputs from the counting means having frequencies less than the frequency of the one-times clock signal with the fine angle control signal to generate a select control signal; and means for producing the phase shifted clock signal from the selected one of the quadrature pairs in response to the select control signal.
Claim 8
Independent Claim
105 words
A method of digital phase shifting comprising the steps of: digitally generating from an input clock signal two sets of complementary clock signals, the clock signals of one set being in quadrature with the clock signals of the other set; combining the two sets of complementary clock signals to form quadrature pairs of the clock signals from the two sets of complementary clock signals; and mixing the clock signals of a selected one of the quadrature pairs as a function of a desired phase shift to produce a phase shifted clock signal representing the input clock signal shifted in phase by the desired phase shift.
Claim 9
Independent Claim
105 words
A method of digital phase shifting comprising the steps of: digitally generating from an input clock signal two sets of complementary clock signals, the clock signals of one set being in quadrature with the clock signals of the other set; combining the two sets of complementary clock signals to form quadrature pairs of the clock signals from the two sets of complementary clock signals; and mixing the clock signals of a selected one of the quadrature pairs as a function of a desired phase shift to produce a phase shifted clock signal representing the input clock signal shifted in phase by the desired phase shift.
Claim 10
Dependent Claim
44 words
The method as recited in claim 7 wherein the digitally generating step comprises the steps of: multiplying the frequency of the input clock signal to produce a multiple-times clock signal; and producing from the multiple-times clock signal the two sets of complementary clock signals.
Claim 11
Dependent Claim
77 words
The method as recited in claim 8 wherein the producing step comprises the steps of: cyclically counting cycles of the multiple-times clock signal, the counting step having N outputs, one output of which provides a one-times clock signal at the frequency of the input clock signal; deriving from the one-times clock signal a quadrature one-times clock signal; and generating from the one-times clock signal and the quadrature one-times clock signal the two sets of complementary clock signals.
Claim 12
Dependent Claim
34 words
The method as recited in claim 9 wherein the generating step comprises the step of converting the one-times clock signal and the quadrature one-times clock signal into the two sets of complementary clock signals.
Claim 13
Dependent Claim
89 words
The method as recited in claim 9 wherein the mixing step comprises the steps of: selecting from the input quadrature pairs in response to a coarse angle control signal the clock signals of the selected one of the quadrature pairs representing a selected quadrant of phase angles; and alternatingly selecting between the clock signals of the selected one of the quadrature pairs in response to a fine angle control signal to produce the phase shifted clock signal, the coarse and fine angle control signals representing the desired phase shift.
Claim 14
Dependent Claim
70 words
The digital phase shifter as recited in claim 11 wherein the alternatingly selecting step comprises the steps of: comparing the outputs from the counting step having frequencies less than the frequency of the one-times clock signal with the fine angle control signal to generate a select control signal; and producing the phase shifted clock signal from the selected one of the quadrature pairs in response to the select control signal.
Claim 15
Dependent Claim
88 words
The digital phase shifter as recited in claim 1 wherein the mixing means comprises: means for selecting from the input quadrature pairs in response to a coarse angle control signal the selected one of the quadrature pairs representing a selected quadrant of phase angles; and means for alternatingly selecting between the clock signals of the selected one of the quadrature pairs in response to a fine angle control signal to produce the phase shifted clock signal, the coarse and fine angle control signals representing the desired phase shift.
Claim 16
Dependent Claim
85 words
The method as recited in claim 7 wherein the mixing step comprises the steps of: selecting from the input quadrature pairs in response to a coarse angle control signal the selected one of the quadrature pairs representing a selected quadrant of phase angles; and alternatingly selecting between the clock signals of the selected one of the quadrature pairs in response to a fine angle control signal to produce the phase shifted clock signal, the coarse and fine angle control signals representing the desired phase shift.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-19 | 2000-05-20 | 2000-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-19 | 2004-05-20 | 2004-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-19 | 2008-05-20 | 2008-11-19 | $7700.00 | Window Closed / Lapsed |