US3686635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated circuit decoder responsiver to two sequential tones, with group call provisions
Assignee: Motorola Solutions Inc
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Filing: 1971-06-09
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Granted: 1972-08-22
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Expires: 1991-06-09
Abstract
Abstract Decoder circuit for use with two tone sequential calling signal, which responds only to two tones of predetermined frequencies, amplitudes, durations and time spacing. The circuit is constructed in integrated circuit form with the components critical to the timing of the tones provided as external components to facilitate use of the decoder in different systems. The circuit includes a series AND gate which actuates an alert tone output in response to tones of the specified frequencies and time relationships. An auxiliary circuit provides group call operation in response to a single tone of long duration. The alert tone can be intermittent or continuous and of different time durations.
Inventors
- 👤 Raymond J Millington
- 👤 John R Rezek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:30
CPC Classifications
H; H04; H04W; H04W88/00; H04W88/02; H04W88/022; H04W88/025; H04W88/027
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
219 words
In a tone decoder which responds to first and second tones of different frequencies which are received sequentially, and wherein the first and second tones are applied to first and second terminals respectively, the combination including: a first circuit connected to the first terminal including threshold detector means for receiving the first tone, integration circuit means including capacitor means, and first trigger circuit means, said threshold detector means being coupled to said capacitor means and causing the same to change its state of charge following termination of the first tone so that the voltage thereacross reaches a predetermined value at a given time following the termination of the first tone, and said trigger circuit means being coupled to said capacitor means and producing a first voltage pulse in response to a voltage across said capacitor means of the predetermined value; a second circuit connected to the second terminal including threshold detector means for receiving the second tone, and trigger means coupled to said detector means and producing a second voltage pulse in response to the second tone; and AND gate means including a first portion coupled to said first circuit and a second portion coupled to said second circuit, said AND gate means producing an output voltage in response to simultaneous occurrence of said first and second voltage pulses.
Claim 2
Dependent Claim
219 words
In a tone decoder which responds to first and second tones of different frequencies which are received sequentially, and wherein the first and second tones are applied to first and second terminals respectively, the combination including: a first circuit connected to the first terminal including threshold detector means for receiving the first tone, integration circuit means including capacitor means, and first trigger circuit means, said threshold detector means being coupled to said capacitor means and causing the same to change its state of charge following termination of the first tone so that the voltage thereacross reaches a predetermined value at a given time following the termination of the first tone, and said trigger circuit means being coupled to said capacitor means and producing a first voltage pulse in response to a voltage across said capacitor means of the predetermined value; a second circuit connected to the second terminal including threshold detector means for receiving the second tone, and trigger means coupled to said detector means and producing a second voltage pulse in response to the second tone; and AND gate means including a first portion coupled to said first circuit and a second portion coupled to said second circuit, said AND gate means producing an output voltage in response to simultaneous occurrence of said first and second voltage pulses.
Claim 3
Dependent Claim
28 words
The combination of claim 1 wherein said first and second circuits are adapted to operate from a supply voltage within the range from 1 volt to 1.5 volts.
Claim 4
Dependent Claim
41 words
The combination of claim 2 wherein said capacitor means causes said threshold detector to respond only to said first tone which continues for a specified time, and acts to delay said first pulse until after the termination of said first tone.
Claim 5
Dependent Claim
49 words
The combination of claim 1 wherein said first circuit, said second circuit and said AND gate means are formed as a hybrid module including an integrated circuit and a thick film base therefor, and wherein said integration circuit means is formed by discrete components external to said hybrid module.
Claim 6
Dependent Claim
48 words
The combination of claim 1 wherein said AND gate means includes said first and second transistors connected in series, and further including a control transistor coupled to said AND gate means and operating in response to conduction of said first and second transistors to provide said output voltage.
Claim 7
Dependent Claim
44 words
The combination of claim 5 further including latching circuit means coupled to said control transistor and to said first circuit means for causing said trigger circuit thereof to operate to continue said first voltage pulse during the period of operation of said control transistor.
Claim 8
Dependent Claim
28 words
The combination of claim 5 further including alert tone generator means, and means coupling said control transistor to said alert tone generator means for rendering the same operative.
Claim 9
Dependent Claim
76 words
The combination of claim 7 wherein said alert tone generator means includes a plurality of amplifier stages each including a transistor and a feedbacK circuit including a twin-T filter, and wherein said transistors of said AND gate means, said control transistor, and said transistors of said tone generator means are provided on an integrated circuit which is supported on a thick film base, and said twin-T filter is formed by components on said thick film base.
Claim 10
Dependent Claim
30 words
The combination of claim 7 wherein said means coupling said control transistor to said alert tone oscillator is an astable multivibrator for providing intermittent operation of said alert tone oscillator.
Claim 11
Dependent Claim
76 words
The combination of claim 9 wherein said astable multivibrator has an element for controlling the timing thereof, and said first circuit, said second circuit, said AND gate means, said alert tone generator means, and said astable multivibrator are formed as a hybrid module including an integrated circuit on a thick film base, and said integrator means and said element for controlling the timing of said astable multivibrator are formed as discrete components external to said module.
Claim 12
Dependent Claim
52 words
The combination of claim 5 further including timer means coupled to said control transistor and operating for a predetermined time period after operation of said control transistor, and means coupling said timer means to said AND gate means for causing the same to produce said output voltage during said predetermined time period.
Claim 13
Dependent Claim
91 words
The combination of claim 1 further including an auxiliary circuit coupled to said second circuit for producing a third voltage pulse in response to the second tone upon continuance thereof for a given time period, and means coupling said auxiliary circuit to said first circuit to apply said third voltage pulse to said trigger means thereof to cause the same to produce said first voltage pulse, whereby said gate means operates to produce said output voltage in response to the second tone alone upon continuance thereof for said given time period.
Claim 14
Dependent Claim
97 words
The combination of claim 12 wherein said auxiliary circuit includes capacitor means, and means for changing the charge of said capacitor means rendered operative in response to the second tone, with the value of said capacitor means being related to said charging means so that the voltage on said capacitor means reaches a predetermined value upon continuation of the second tone for said given time period, and switch means coupled to said capacitor means and rendered operative in response to said capacitor means charging to a voltage of said predetermined voltage to produce said third voltage pulse.
Claim 15
Dependent Claim
36 words
The combination of claim 12 wherein said auxiliary circuit is provided as a hybrid module including an integrated circuit and a thick film base, and wherein said capacitor means is provided on said thick film base.
Claim 16
Dependent Claim
62 words
The combination of claim 12 further including alert tone generator means and astable multivibrator means coupling said control transistor to said alert tone generator means for causing intermittent operation thereof, and means coupling said auxiliary circuit to said astable multivibrator means to disable the same in response to operation of said auxiliary circuit, whereby said tone generator means produces a continuous tone.
References Cited (Backward Citations)
US3597690A
Cited
US3581283A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |