US3772681A
Expired / Lapsed
US
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Frequency synthesiser
Assignee: Post Office
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Filing: 1971-10-12
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Granted: 1973-11-13
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Expires: 1991-10-12
Abstract
Abstract A frequency synthesiser, which may be used in Modem systems MCVFT systems and F.M. receivers, produces a predetermined waveform signal by using the digital values of incremental points on the waveform, which values are selected in a sequence determined by a address selection arrangement from a digital storage memory of the read-only type. The output from the readonly memory is a digital signal which may be filtered and distributed to a number of channels or it may be passed by way of a digital-to-analogue converter to generate the predetermined phase continuous waveform.
Inventors
- 👤 G Skingle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:37
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/02; H04L5/06; G; G06; G06F; G06F1/00; G06F1/02; G06F1/03; G06F1/035; G06F1/0353; H04J; H04J1/00; H04J1/02; H04J1/06; H04L27/00; H04L27/18; H04L27/20; H04L27/2003
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
148 words
A frequency synthesizer for providing a signal having a predetermined continuous function analogue waveform, said synthesizer comprising a source of clock frequency signals; a digital memory arranged to contain the amplitude values of a series of incremental points on the waveforms; selection means for composing an address for said digital memory and applying said address to said memory at a clock frequency derived from said clock frequency source, said selection means being arranged to compose said address from a plurality of data input signals, a first set of which is preset, and a second set of which is derived from an output of said memory; and digital to analogue converter means arranged to produce sample pulses and said converter means being coupled to a filter means to convert the series of sample pulses representing incremental points on the waveform to a continuous waveform having a predetermined selectable frequency.
Claim 2
Dependent Claim
148 words
A frequency synthesizer for providing a signal having a predetermined continuous function analogue waveform, said synthesizer comprising a source of clock frequency signals; a digital memory arranged to contain the amplitude values of a series of incremental points on the waveforms; selection means for composing an address for said digital memory and applying said address to said memory at a clock frequency derived from said clock frequency source, said selection means being arranged to compose said address from a plurality of data input signals, a first set of which is preset, and a second set of which is derived from an output of said memory; and digital to analogue converter means arranged to produce sample pulses and said converter means being coupled to a filter means to convert the series of sample pulses representing incremental points on the waveform to a continuous waveform having a predetermined selectable frequency.
Claim 3
Dependent Claim
39 words
A frequency synthesizer as claimed in claim 1 in which selection means is an arithmetic unit including a digital signal adder arranged to add a predetermined increment derived from said first set of inputs to each consecutive memory address.
Claim 4
Dependent Claim
25 words
A frequency synthesizer as claimed in claim 2 in which said digital memory is arranged to store the incremental amplitude values of a sine waveform.
Claim 5
Dependent Claim
107 words
A frequency synthesizer for providing a phase continuous function signal when switched between a number of predetermined frequencies, said synthesizer comprising: a clock frequency source; a digital read-only memory arranged to contain the amplitude values of a series of incremental points on a sine waveform; selection means for composing an address for said read-only memory and applying said address to the memory at a clock frequency obtained from the clock frequency source; data input switching means controlling the selection means so as to address the desired amplitude increment in said memory; and a memory output converter arranged to apply the selected predetermined amplitude sample to a filter.
Claim 6
Dependent Claim
107 words
A frequency synthesizer for providing a phase continuous function signal when switched between a number of predetermined frequencies, said synthesizer comprising: a clock frequency source; a digital read-only memory arranged to contain the amplitude values of a series of incremental points on a sine waveform; selection means for composing an address for said read-only memory and applying said address to the memory at a clock frequency obtained from the clock frequency source; data input switching means controlling the selection means so as to address the desired amplitude increment in said memory; and a memory output converter arranged to apply the selected predetermined amplitude sample to a filter.
Claim 7
Dependent Claim
32 words
A frequency synthesizer as claimed in claim 4 in which a plurality of channels are multiplexed by means of an input multiplexer driven at the clock frequency from said clock frequency source.
Claim 8
Dependent Claim
22 words
A frequency synthesizer as claimed in claim 5 in which the memoRy output converter signal is applied to a multiplexed digital filter.
Claim 9
Dependent Claim
42 words
A frequency synthesizer as claimed in claim 5 in which the signal from said memory output converter is fed to an output channel distributor and said signal from the memory output converter is translated to an analogue signal in a digital-to-analogue converter.
Claim 10
Dependent Claim
99 words
A frequency synthesizer for providing a continuous function signal having a predetermined waveform said synthesizer comprising: a clock frequency source; a digital memory having a multiple bit word store arranged to contain the digital amplitude values of incremental points on the waveform; selection means for composing an address for said digital memory and applying said address to the memory at a clock frequency produced from said clock frequency source; and a digital-to-analogue converter means for producing the predetermined analogue waveform from the digital output of said memory so as to generate time-staggered amplitude values for a plurality of channels.
Claim 11
Dependent Claim
99 words
A frequency synthesizer for providing a continuous function signal having a predetermined waveform said synthesizer comprising: a clock frequency source; a digital memory having a multiple bit word store arranged to contain the digital amplitude values of incremental points on the waveform; selection means for composing an address for said digital memory and applying said address to the memory at a clock frequency produced from said clock frequency source; and a digital-to-analogue converter means for producing the predetermined analogue waveform from the digital output of said memory so as to generate time-staggered amplitude values for a plurality of channels.
Claim 12
Dependent Claim
22 words
A frequency synthesizer as claimed in claim 8 in which the digital memory consists of a read-only memory of sine table values.
Claim 13
Dependent Claim
32 words
A frequency synthesizer as claimed in claim 9 including a data input section and an inhibit selection unit arranged to inhibit those inputs to said data input section which are not required.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |