US4870384A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency or phase modulation
Assignee: Aeroflex Ltd
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Filing: 1988-12-21
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Granted: 1989-09-26
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Expires: 2008-12-21
Abstract
Abstract A frequency or phase modulator, in particular a DC-coupled frequency modulation synthesizer, comprises a voltage-controlled oscillator (1) in series with a divider (2) in a phase-locked loop, and an analog-to-digital converter (17) connected to control the divider in accordance with an input analog modulation signal. The converter (17), preferably a one-bit charge-balanced converter, has a noise-shaped frequency response to reduce noise at frequencies below the loop-bandwidth.
Inventors
- 👤 Neil E. Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:54
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/095; H03C3/0916; H03C3/0925; H03C3/0933; H03C3/0941
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
65 words
A frequency or phase modulator comprising a voltage-controlled oscillator in series with a divider in a phase-locked loop, and an analogue-to-digital converter connected to control the divider in accordance with an analogue modulation signal, the analogue-to-digital converter having a noise-shaped frequency response so as to reduce noise at frequencies below the loop bandwidth to substantially below the white noise level which would prevail without noise-shaping.
Claim 2
Dependent Claim
65 words
A frequency or phase modulator comprising a voltage-controlled oscillator in series with a divider in a phase-locked loop, and an analogue-to-digital converter connected to control the divider in accordance with an analogue modulation signal, the analogue-to-digital converter having a noise-shaped frequency response so as to reduce noise at frequencies below the loop bandwidth to substantially below the white noise level which would prevail without noise-shaping.
Claim 3
Dependent Claim
19 words
A modulator as claimed in claim 1, comprising means for applying the input modulation signal to the voltage-controlled oscillator.
Claim 4
Dependent Claim
49 words
A modulator as claimed in claim 2, in which the components of the modulator have characteristics selected such that at the phase-locked loop bandwidth the gain of the modulation route via the analogue-to-digital converter is substantially equal to the gain of the modulation applied to the voltage controlled oscillator.
Claim 5
Dependent Claim
16 words
A modulator as claimed in claim 1, in which the analogue-to-digital converter is a one-bit converter.
Claim 6
Dependent Claim
29 words
A modulator according to claim 1, in which the output of the analogue-to-digital converter is connected to a control input of the divider by way of digital control means.
Claim 7
Dependent Claim
54 words
A modulator as claimed in claim 5, in which the control means for the divider comprises at least two registers and means responsive to a signal from the analogue-to-digital converter to select, in accordance with that signal, the contents of one of the registers and to control the divider in accordance with those contents.
Claim 8
Dependent Claim
16 words
A modulator as claimed in claim 5, in which the divider is a fractional N divider.
Claim 9
Dependent Claim
16 words
A modulator as claimed in claim 6, in which the divider is a fractional N divider.
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) | 1992-09-25 | 1993-03-27 | 1993-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-25 | 1997-03-27 | 1997-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-25 | 2001-03-27 | 2001-09-26 | $7700.00 | Window Closed / Lapsed |