US3719832A
Expired / Lapsed
US
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Time division multiplexer using charge storage diode line circuits
Assignee: AT&T Inc
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Filing: 1971-06-16
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Granted: 1973-03-06
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Expires: 1991-06-16
Abstract
Abstract A charge storage diode in a line circuit is charged to different levels by a signal current driven therethrough in the forward direction so that diode charge tracks the instantaneous signal amplitude. A reverse drive is applied to the diode, at a time when it is desired to sample the line signal current amplitude, for transferring the diode charge to a precharged capacitor connected in series with the diode in a separate circuit from the signal current circuit. The reverse drive is maintained for a sufficient time to remove substantially all charge from the diode in the presence of a maximum anticipated precharge level on the capacitor. A plurality of such diode signal current circuits, each having individual ground return connection points to a common ground plane, are fanned into a single capacitor connected to a further connection point of the same plane; and the respective diode reverse drives are controlled so that the capacitor receives samples of line signal currents from the diode circuits in a predetermined sequence.
Inventors
- 👤 S Waaben
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:06
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/74; H03K17/76; H03K17/56; H03K17/60; H03K17/62; H03K17/6257
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
161 words
In combination, a plurality of individual line signal circuits, a plurality of charge storage diodes, each being connected in series in a different one of said circuits and poled for forward diode conduction of line signal in such circuit, a common sampling capacitor, means for connecting said capacitor in a different capacitordiode series circuit with each of said diodes, said line circuits and said capacitor-diode series circuits including a common ground reference means with connections thereto at different points for said line circuits and said capacitordiode series circuits, said reference means being subject to potential differences therein between connection points thereto, said potential differences being of significant magnitude in relation to line signals in said line signal circuits, and means for selectively applying a discharge current to one of said capacitor-diode series circuits in the reverse conduction direction for the diode therein substantially completely to remove to said capacitor any charge theretofore accumulated in such diode in its line signal circuit.
Claim 2
Dependent Claim
161 words
In combination, a plurality of individual line signal circuits, a plurality of charge storage diodes, each being connected in series in a different one of said circuits and poled for forward diode conduction of line signal in such circuit, a common sampling capacitor, means for connecting said capacitor in a different capacitordiode series circuit with each of said diodes, said line circuits and said capacitor-diode series circuits including a common ground reference means with connections thereto at different points for said line circuits and said capacitordiode series circuits, said reference means being subject to potential differences therein between connection points thereto, said potential differences being of significant magnitude in relation to line signals in said line signal circuits, and means for selectively applying a discharge current to one of said capacitor-diode series circuits in the reverse conduction direction for the diode therein substantially completely to remove to said capacitor any charge theretofore accumulated in such diode in its line signal circuit.
Claim 3
Dependent Claim
161 words
In combination, a plurality of individual line signal circuits, a plurality of charge storage diodes, each being connected in series in a different one of said circuits and poled for forward diode conduction of line signal in such circuit, a common sampling capacitor, means for connecting said capacitor in a different capacitor-diode series circuit with each of said diodes, said line circuits and said capacitor-diode series circuits including a common ground reference means with connections thereto at different points for said line circuits and said capacitor-diode series circuits, said reference means being subject to potential differences therein between connection points thereto, said potential differences being of significant magnitude in relation to line signals in said line signal circuits, and means for selectively applying a discharge current to one of said capacitor-diode series circuits in the reverse conduction direction for the diode therein substantially completely to remove to said capacitor any charge theretofore accumulated in such diode in its line signal circuit.
Claim 4
Dependent Claim
161 words
In combination, a plurality of individual line signal circuits, a plurality of charge storage diodes, each being connected in series in a different one of said circuits and poled for forward diode conduction of line signal in such circuit, a common sampling capacitor, means for connecting said capacitor in a different capacitor-diode series circuit with each of said diodes, said line circuits and said capacitor-diode series circuits including a common ground reference means with connections thereto at different points for said line circuits and said capacitor-diode series circuits, said reference means being subject to potential differences therein between connection points thereto, said potential differences being of significant magnitude in relation to line signals in said line signal circuits, and means for selectively applying a discharge current to one of said capacitor-diode series circuits in the reverse conduction direction for the diode therein substantially completely to remove to said capacitor any charge theretofore accumulated in such diode in its line signal circuit.
Claim 5
Dependent Claim
61 words
The combination in accordance with claim 1 in which each of said diodes is a semiconductor diode which stores charges for a time period which is a function of charge carrier recombination time of the diode, and said time period is smaller than the period of a predetermined maximum frequency component of signals in the line signal circuit of such diode.
Claim 6
Dependent Claim
53 words
The combination in accordance with claim 1 in which each of said line signal circuits includes, a signal source-isolating diode, and means connecting said isolating Diode in series with the charge storage diode of the same line signal circuit, and poled for forward conduction in the same direction as such charge storage diode.
Claim 7
Dependent Claim
68 words
The combination in accordance with claim 1 in which said means for selectively applying discharge current in each of said line signal circuits comprises, a line-isolating diode, and means connecting the last-mentioned diode in series in the capacitor-diode series circuit for such line between the capacitor and charge storage diode of such circuit, said isolating diode being poled for forward conduction of said discharge current in such circuit.
Claim 8
Dependent Claim
55 words
The combination in accordance with claim 5 which comprises in addition means for recurrently discharging said sampling capacitor to a predetermined voltage level which is of at least sufficient amplitude for biasing to a non-conducting condition said line-isolating diode of any line circuit which is conducting said line signal in the charge storage diode thereof.
Claim 9
Dependent Claim
25 words
The combination in accordance with claim 1 in which said connecting means comprises a substantially nonreactive connection between said capacitor and each of said diodes.
Claim 10
Dependent Claim
79 words
The combination in accordance with claim 1 in which means are provided for recurrently discharging said sampling capacitor to a predetermined voltage level, control means are provided to actuate said applying means for said line signal circuits in a predetermined sequence of such circuits and for actuating said recurrent discharging means once after each actuation of one of said applying means, and substantially nonreactive circuits couple said control means for actuating said applying means and said recurrent discharging means.
Claim 11
Dependent Claim
38 words
The combination in accordance with claim 1 in which means are provided for discharging said sampling capacitor to a predetermined voltage level prior to each connection of such capacitor in a different one of said capacitor-diode series circuits.
Claim 12
Dependent Claim
54 words
The combination in accordance with claim 1 in which each of said line signal circuits is connected to a different point on said reference means through an impedance of value substantially the same as the characteristic impedance of said line signal circuit and of said discharge current applying means for such line signal circuit.
Claim 13
Dependent Claim
53 words
The combination in accordance with claim 1 in which each of said line signal circuits includes an impedance which is also connected in shunt with respect to said discharge current applying means and which has an impedance value substantially the same as the characteristic impedances of such line circuit and said applying means.
Claim 14
Dependent Claim
45 words
The combination in accordance with claim 1 in which each of said line signal circuits comprises EXCLUSIVE OR logic means, including said applying means, for connecting said charge storage diode to be alternately charged by said line signal current and discharged by said applying means.
Claim 15
Dependent Claim
111 words
The combination in accordance with claim 1 in which each of said line signal circuits comprises a line switch selectably actuatable for connecting a terminal of the charge storage diode of the same line signal circuit to a ground reference point, a potential source connected in parallel with said line switch, and poled for driving current through the charge storage diode of such line circuit in the reverse direction for such diode in said discharge current applying means, and means selectably opening the line switch of one of said line signal circuits to interrupt the charging of the charge storage diode therein and thereby also actuate said discharge current applying means.
Claim 16
Dependent Claim
42 words
The combination in accordance with claim 12 in which said line switch opening means comprises means selectably actuating the line switches of said line signal circuits one at a time in a predetermined sequence for opening said line switches in such sequence.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |