US3920897A
Expired / Lapsed
US
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Electric pulse train generators and frequency synthesisers
Assignee: GPT INTERNATIONAL Ltd
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Filing: 1974-04-24
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Granted: 1975-11-18
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Expires: 1994-04-24
Abstract
Abstract A pulse train generator arrangement in which a required pulse repetition rate is achieved by selection of one or more of a plurality of interlaced trains of pulses of different repetition rates and by selective cancellation of some of the pulses in the selected trains. In a voice-frequency tone signalling system for example two tones of differing frequencies are obtained using such a generator arrangement by selectively subtracting by cancellation a pulse train of a relatively low repetition rate from a pulse train of higher repetition rate followed by repetition rate division and filtering.
Inventors
- 👤 James Grant
- 👤 Clive Rowland Warburton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:12
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
128 words
An electric pulse train generator arrangement comprising generating means for generating a plurality of interlaced pulse trains each having a different repetition rate, first means for deriving from at least one of said pulse trains a first intermediate pulse train, second means selectively to pass at least one of said pulse trains in dependence upon a control signal applied thereto to form a second intermediate pulse train having a lower pulse repetition rate than said first intermediate pulse train, and subtraction means for cancelling from said first intermediate pulse train one pulse in respect of each pulse in said second intermediate pulse train to provide an output pulse train having a repetition rate equal to the difference in repetition rates between said first and second intermediate pulse trains.
Claim 2
Dependent Claim
128 words
An electric pulse train generator arrangement comprising generating means for generating a plurality of interlaced pulse trains each having a different repetition rate, first means for deriving from at least one of said pulse trains a first intermediate pulse train, second means selectively to pass at least one of said pulse trains in dependence upon a control signal applied thereto to form a second intermediate pulse train having a lower pulse repetition rate than said first intermediate pulse train, and subtraction means for cancelling from said first intermediate pulse train one pulse in respect of each pulse in said second intermediate pulse train to provide an output pulse train having a repetition rate equal to the difference in repetition rates between said first and second intermediate pulse trains.
Claim 3
Dependent Claim
40 words
An electric pulse train generator arrangement in accordance with claim 1 wherein said first means comprises first combining means and said first intermediate pulse train comprises a combination of at least two of said pulse trains from said generating means.
Claim 4
Dependent Claim
20 words
An electric pulse train generator arrangement in accordance with claim 2 wherein said first combining means comprises an OR gate.
Claim 5
Dependent Claim
52 words
An electric pulse train generator arrangement in accordance with claim 1 wherein said generating means comprises a pulse generator providing pulses at a high repetition rate and a succession of divide-by-two stages, and said pulse trains, having repetition rates related by factors of two, are derived from respective ones of said stages.
Claim 6
Dependent Claim
81 words
An electric pulse train generator arrangement in accordance with claim 1 wherein said subtraction means comprises a bistable circuit, means to set and bistable circuit in response to a pulse in said second intermediate pulse train, means to reset said bistable Circuit in response to a pulse in said first intermediate pulse train, and output gating means to pass pulses occurring in said first intermediate pulse train to an output point only when the bistable circuit is in its reset condition.
Claim 7
Dependent Claim
30 words
An electric pulse train generator arrangement in accordance with claim 5 wherein the first intermediate pulse train is applied to said output gating means by way of a delay network.
Claim 8
Dependent Claim
66 words
An electric pulse train generator arrangement in accordance with claim 1 wherein said second means comprises first gating means selectively to pass one of said pulse trains, in dependence upon the value of a control signal, to second gating means to which is also applied at least one other of said pulse trains, the output of said second gating means forming said second intermediate pulse train.
Claim 9
Dependent Claim
22 words
An electric pulse train generator arrangement in accordance with claim 7 wherein said control signal is derived from a two-state telegraphy signal.
Claim 10
Dependent Claim
47 words
An electric pulse train generator arrangement in accordance with claim 1 wherein said output pulse train is applied to a divider circuit to derive a pulse train having a repetition rate much lower than the repetition rate of any of said pulse trains from said generating means.
Claim 11
Dependent Claim
64 words
Transmitter terminal apparatus for a frequency shift keyed telegraphy system in which information is transmitted as at least two alternate tones of different frequencies comprising a pulse train generator in accordance with claim 1 including means for controlling the second means such that pulse repetition rate of the output of the pulse train generator is equal to the frequency of the instantaneously required tone.
Claim 12
Dependent Claim
109 words
Receiver terminal apparatus for a frequency shift keyed telegraphy system in which information is received as at least two alternate tones of different frequencies, comprising a pulse train generator in accordance with claim 1, comparison means for comparing the relative phases of a signal derived from the received tone and of a signal derived from the output of the pulse generator and for deriving a control signal from this comparison, this control signal being utilised to control said second means so that the pulse train generator is phase-locked to the received tone and the value of the control signal is a measure of the frequency of the received tone.
Claim 13
Dependent Claim
28 words
Receiver terminal apparatus in accordance with claim 11 including means to square the received tones to form respective pulse trains which constitute said signals derived from the tones.
Claim 14
Dependent Claim
73 words
Receiver terminal apparatus in accordance with claim 11 wherein the pulse repetition rates of the pulse train generator outputs are substantial multiples of the tone frequencies and are divided down by a fixed ratio to rates which are controlled to be respectively lower than the rate of the lower of said signals derived from the received tones or higher than the rate of the higher of said signals derived from the received tones.
Claim 15
Dependent Claim
25 words
Receiver terminal apparatus in accordance with claim 11 wherein the output of the comparator is passed through a low-pass filter to derive said control signal.
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) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |