US3603744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Line tap unit for telephone system
Assignee: Superior Continental Corp
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Filing: 1969-07-07
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Granted: 1971-09-07
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Expires: 1989-07-07
Abstract
Abstract A line tap unit for use in combination with telephone facilities including a central office station having a plurality of central office terminals comprised of channel units with receiver and transmitter sections from which extend a two-conductor transmission line. The line tap units connected to each transmission line at locations remote from the central office terminal include a receiver section operable at the same frequency as a transmitter section of one central office channel unit and a transmitter section operable at another frequency which is the same frequency as a receiver section of the same central office channel unit. Each line tap unit has means for extracting low frequency power from the transmission line to operate its receiver and transmitter sections and coordination control means responsive to the signal received from its central office terminal for automatically adjusting the signal output of its transmitter section so that all signals arrive at a central office terminal at the same level. The coordination control means includes regulator means for comparing a received signal against a fixed reference and for producing a feedback signal proportional to the difference between the received signal and the fixed reference.
Inventors
- 👤 Lester Q Krasin
- 👤 Clifford E Greene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:20
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/10; H04J; H04J1/00; H04J1/02; H04J1/10; H04Q11/02; H04Q5/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
95 words
A line tap unit adapted for connection with a two-conductor transmission line extending from a central office terminal unit of a telephone distribution system, said line tap unit comprising: a receiver section and a transmitter section adapted to operate at different predetermined frequencies, said receiver section including regulator means for comparing a received signal against a fixed reference and for producing a feedback signal within the unit proportional to the difference between the received signal and the fixed reference, said transmitter section including attenuator means responsive to said feedback signal for adjusting its output level.
Claim 2
Dependent Claim
95 words
A line tap unit adapted for connection with a two-conductor transmission line extending from a central office terminal unit of a telephone distribution system, said line tap unit comprising: a receiver section and a transmitter section adapted to operate at different predetermined frequencies, said receiver section including regulator means for comparing a received signal against a fixed reference and for producing a feedback signal within the unit proportional to the difference between the received signal and the fixed reference, said transmitter section including attenuator means responsive to said feedback signal for adjusting its output level.
Claim 3
Dependent Claim
124 words
The line tap unit as described in claim 1 including: filter means in said receiver section for selecting energy being carried by said transmiSsion line at a predetermined carrier frequency through a first coupling transformer associated with the particular channel unit; said attenuator means including a first controllable attenuator connected to said filter means in said receiver section and a second controllable attenuator in said transmitter section of the line tap unit; amplifier means connected to said first controllable attenuator; means for detecting the amplitude of the output of said amplifier means, said regulator means being connected to receive a signal from said means for detecting and providing an output signal proportional to a fixed predetermined reference level for controlling said first controllable attenuator.
Claim 4
Dependent Claim
63 words
The line tap unit as described in claim 2 including a voice-frequency low-pass filter for deriving the voice-frequency energy in the output signal from said means for detecting while blocking the carrier-frequency energy; means for amplifying and expanding the derived voice-frequency energy and providing it at output terminals of the line tap unit through a second coupling transformer connected to a subscriber''s telephone.
Claim 5
Dependent Claim
111 words
The line tap unit as described in claim 3 which wherein said transmitter section comprises: a compressor means connected to said second coupling transformer for amplifying and dynamically compressing the voice-frequency energy derived therefrom; oscillator means for creating carrier-frequency energy of a predetermined frequency; modulator means for impressing voice-frequency energy on the carrier-frequency energy derived from said oscillator means, said second controlled attenuator being connected to said modulator means and to said first controlled attenuator and thereby responsive to the output of said regulator for controlling the signal level of the output from the transmitter section of the unit which is coupled to said transmission line through said first coupling transformer.
Claim 6
Dependent Claim
114 words
The line tap unit as described in claim 3 wherein said regulator means in said receiver section comprises: a transistor with base, collector and emitter terminals having its base terminal connected to said means for detecting and thereby supplying one component of an input signal; a preset reference voltage circuit connected to the emitter of said transistor and to the base lead connection from said means for detecting; and means connecting the collector of said transistor to said first controlled attenuator, whereby said transistor will conduct more current through its collector connection when the base-bias voltage exceeds the emitter voltage, thereby causing the attenuator means to control the transmitter output level of the unit.
Claim 7
Dependent Claim
73 words
The line tap unit as described in claim 5 wherein said first and second attenuators are comprised of a plurality of diodes connected in series in a lead extending from said collector connection of said transistor and a ground potential junction and connected at intermediate junctions to said receiver section between said filter means and said amplifier and to the transmitter section of said line tap unit between its modulator and its amplifier.
Claim 8
Dependent Claim
178 words
The line tap unit of claim 3 wherein said means in said receiver section for amplifying and expanding the received voice-frequency energy comprises: a DC control amplifier and an amplifier and an amplifier transistor connected in parallel; means in the receiver section for supplying voice-frequency energy to the amplifier input and to a base connected lead of said transistor; resistor means in a lead connecting the transistor collector and said base lead and resistor means in a lead connecting the transistor emitter and the base lead; means for controlling the gain of said amplifier transistor including a capacitor having a bypassing impedance and a diode having a series impedance, both arranged in a network connected to the emitter of said transistor; means for connecting said diode to the output of said control amPlifier, thereby controlling its series impedance, the diode series impedance being thus responsive to the voice-frequency energy input to the expander means; whereby an increase in input level to the expander will result in an even greater increase in its output level from the transistor collector
Claim 9
Dependent Claim
119 words
The line tap unit as described in claim 4 wherein said compressor means comprises: a resistor and a diode in series forming a variable attenuator having an input supplied with voice-frequency energy at a relatively high level, said diode having a variable shunt impedance for controlling the amount of attenuation; a DC control amplifier responsive to the signal level at its input and having an output connected to said diode; a voice-frequency amplifier; means for capacitively coupling voice-frequency energy through said variable attenuator and feeding it into said voice-frequency amplifier; means for supplying the output from said voice-frequency amplifier and thus from said compressor means to said control amplifier and also to said modulation means of said transmitter section.
Claim 10
Dependent Claim
104 words
A line tap unit adapted for connection with a transmission line extending from a central office terminal unit of a telephone system to form a subscriber''s station remote from the central office, said tap unit comprising: a receiver section and a transmitter section adapted to operate at different predetermined frequencies and including an automatic coordination control means comprising an automatic gain-control means in said receiver section for comparing a received signal against a fixed reference and providing a feedback signal, and attenuator means in said transmitter section connected to and controlled by said automatic gain-control means for adjusting the output of said transmitter section.
Claim 11
Dependent Claim
104 words
A line tap unit adapted for connection with a transmission line extending from a central office terminal unit of a telephone system to form a subscriber''s station remote from the central office, said tap unit comprising: a receiver section and a transmitter section adapted to operate at different predetermined frequencies and including an automatic coordination control means comprising an automatic gain-control means in said receiver section for comparing a received signal against a fixed reference and providing a feedback signal, and attenuator means in said transmitter section connected to and controlled by said automatic gain-control means for adjusting the output of said transmitter section.
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) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |