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US3671885A
Expired / Lapsed
US
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High frequency signal routing devices for use in catv systems
Assignee: Lindsay Specialty Products Ltd
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Filing: 1970-12-02
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Granted: 1972-06-20
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Expires: 1990-12-02
Abstract
Abstract Passive devices for signal routing such as directional couplers, hybrid splitters and power inserters, for use in CATV or similar signal distribution systems having improved operating characteristics are obtained by the incorporation of pi-section high-pass filters into such devices. Conventional splitters and directional couplers are modified by the addition of inductances and capacitances so that the required pi-section high-pass filters are formed, with one inductive element of such a filter being constituted by an inductive deviation, for example, a leakage inductance of an existing component of such a device. Improved radiofrequency signal return losses and inter-tap isolation are provided over a much greater frequency range than was heretofore possible.
Inventors
- 👤 Frank C Pennypacker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:15
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/10; H04N7/102; H04N7/104; H03; H03H; H03H7/00; H03H7/48; H03H7/482
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
283 words
A signal routing device for use as a directional coupler having at least three two-pole terminals with first poles of all said terminals being electrically inter-connected by a base conductor and with second poles of all said terminals being coupled together in said device for the passage of electrical signals therebetween and for the passage of radiofrequency signals between first, second, and third terminals and, which includes a pi-section high-pass filter connected between said first and second ones of said terminals and said first and third ones of said terminals to provide a radiofrequency signal return loss of at least about 20 decibels at said first, second, and third ones of said terminals over an extended radiofrequency range, in which said first one of said terminals is serially connected through a first coupling capacitor to a first inductor effectively connected in turn to said second one of said terminals, in which said first one of said terminals is effectively grounded through a second inductor to said base conductor, in which said first inductor is effectively grounded intermediate its ends through a third inductor to said base conductor whereby said first, second and third inductors and said coupling capacitor together constitutes said pi-section high-pass filter for the passage of radiofrequency signals from said first one of said terminals to said second one of said terminals at a first radiofrequency signal attenuation value, and in which said third one of said terminals is inductively coupled to said first inductor for the passage of radiofrequency signals from said first one of said terminals to said third one of said terminals at a second radio frequency signal attenuation value greater than said first radiofrequency signal attenuation value.
Claim 2
Dependent Claim
283 words
A signal routing device for use as a directional coupler having at least three two-pole terminals with first poles of all said terminals being electrically inter-connected by a base conductor and with second poles of all said terminals being coupled together in said device for the passage of electrical signals therebetween and for the passage of radiofrequency signals between first, second, and third terminals and, which includes a pi-section high-pass filter connected between said first and second ones of said terminals and said first and third ones of said terminals to provide a radiofrequency signal return loss of at least about 20 decibels at said first, second, and third ones of said terminals over an extended radiofrequency range, in which said first one of said terminals is serially connected through a first coupling capacitor to a first inductor effectively connected in turn to said second one of said terminals, in which said first one of said terminals is effectively grounded through a second inductor to said base conductor, in which said first inductor is effectively grounded intermediate its ends through a third inductor to said base conductor whereby said first, second and third inductors and said coupling capacitor together constitutes said pi-section high-pass filter for the passage of radiofrequency signals from said first one of said terminals to said second one of said terminals at a first radiofrequency signal attenuation value, and in which said third one of said terminals is inductively coupled to said first inductor for the passage of radiofrequency signals from said first one of said terminals to said third one of said terminals at a second radio frequency signal attenuation value greater than said first radiofrequency signal attenuation value.
Claim 3
Dependent Claim
71 words
A signal routing device as claimed in claim 1 in which said second one of said terminals is connected to said first inductor through a second coupling capacitor and in which fourth inductor is connected to said second one of said terminals effectively to ground said second one of said terminals to said base conductor to provide a five-element pi-section high-pass filter between said first and second ones of said terminals.
Claim 4
Dependent Claim
55 words
A signal routing device as claimed in claim 2 in which said second and fourth inductors are connected to said base conductor through a grounding capacitor to permit the passage of alternating electric current up to about 400 Hz between said first and second ones of said terminals serially through said second and third inductors.
Claim 5
Dependent Claim
116 words
A signal routing device as claimed in claim 2 in which said first inductor comprises a primary winding of a current-dividing transformer, said primary winding being serially connected between said first and second coupling capacitors, said primary winding of said current-dividing transformer being serially grounded to said base conductor through a primary winding of a voltage-dividing transformer and said current-dividing transformer including a secondary winding having a first end grounded to said base conductor and a second end connected to a secondary winding of said voltage-dividing transformer, and in which said secondary winding of said voltage-dividing transformer is connected to said third one of said terminals and serially grounded through a resistor to said base conductor.
Claim 6
Dependent Claim
143 words
A signal routing device as claimed in claim 4 in which each of said first and second coupling capacitors has a capacitance of from about 500 to about 1,500 picofarads and in which each of said second and fourth inductors has an inductance of from about 7 to about 12 microhenries to provide a radiofrequenCy signal attenuation value of from about 0.3 to about 1.5 decibels with a radiofrequency signal return loss of at least about 5 MHz to about 300 MHz from said first one to said second one of said terminals and a radiofrequency signal attenuation value of from about 8 to about 16 decibels with a radiofrequency signal return loss of at least about 25 decibels over said radiofrequency range of from about 5 MHz to about 300 MHz from said first one to said third one of said terminals.
Claim 7
Dependent Claim
61 words
A signal routing device as claimed in claim 5 in which said second and fourth inductors are connected to said base conductor through a grounding capacitor having a capacitance of at least about 0.005 microfarads to permit the passage of alternating electrical current having a frequency of up to about 60 Hz between said first and second ones of said terminals.
Claim 8
Dependent Claim
48 words
A signal routing device as claimed in claim 5 in which said second and fourth inductors are connected to said base conductor to permit the passage of alternating electrical current having a frequency of up to about 60 Hz between said first and second ones of said terminals.
Claim 9
Dependent Claim
213 words
A signal routing device having at least three two-pole terminals with first poles of all said terminals being electrically inter-connected by a base conductor and with second poles of all said terminals being coupled together in said device for the passage of electrical signals therebetween and for the passage of radiofrequency signals between first, second, and third terminals and, which includes a pi-section high-pass filter connected between said first and second ones of said terminals and said first and third ones of said terminals to provide a radiofrequency signal return loss of at least about 20 decibels at said first, second, and third ones of said terminals over an extended radiofrequency range, in which said pi-section high-pass filter includes a first coupling capacitor connected between said first one of said terminals and an autotransformer inductor which is effectively serially connected between said first coupling capacitor and said base conductor, and a first inductor effectively connected between said first one of said terminals and said base conductor, and in which said second and third ones of said terminals are inductively coupled to said autotransformer inductor for the passage of radio frequency signals between said first one of said terminals and said second and third ones of said terminals over said extended radio frequency range.
Claim 10
Dependent Claim
213 words
A signal routing device having at least three two-pole terminals with first poles of all said terminals being electrically inter-connected by a base conductor and with second poles of all said terminals being coupled together in said device for the passage of electrical signals therebetween and for the passage of radiofrequency signals between first, second, and third terminals and, which includes a pi-section high-pass filter connected between said first and second ones of said terminals and said first and third ones of said terminals to provide a radiofrequency signal return loss of at least about 20 decibels at said first, second, and third ones of said terminals over an extended radiofrequency range, in which said pi-section high-pass filter includes a first coupling capacitor connected between said first one of said terminals and an autotransformer inductor which is effectively serially connected between said first coupling capacitor and said base conductor, and a first inductor effectively connected between said first one of said terminals and said base conductor, and in which said second and third ones of said terminals are inductively coupled to said autotransformer inductor for the passage of radio frequency signals between said first one of said terminals and said second and third ones of said terminals over said extended radio frequency range.
Claim 11
Dependent Claim
47 words
A signal routing device as claimed in claim 8 in which said autotransformer inductor is connected intermediate its ends to a center tap of a power-splitting inductor serially connected between said second and third ones of said terminals with a shunt resistor connected across said power-splitting inductor.
Claim 12
Dependent Claim
76 words
A signal routing device as claimed in claim 9 in which said second and third ones of said terminals are connected to said power-splitting inductor through second and third coupling capacitors respectively and in which said second and third ones of said terminals are effectively connected to said base conductor through second and third inductors respectively effectively to provide second and third pi-section high-pass filters connected to said second and third ones respectively of said terminals.
Claim 13
Dependent Claim
51 words
A signal routing device as claimed in claim 10 in which said center tap of said power-splitting inductor is connected to said base conductor through a first grounding capacitor to provide a T-section low-pass filter between said second and third ones of said terminals and said first one of said terminals.
Claim 14
Dependent Claim
79 words
A signal routing device as claimed in claim 11 in which each of said first, second and third inductors has an inductance of from about 6 to about 10 microhenries and in which each of said first, second and third coupling capacitors has a capacitance of from about 500 to About 1,500 picofarads to provide a radiofrequency signal return loss of at least about 25 decibels over said radiofrequency range of from about 5 MHz to about 300 MHz.
Claim 15
Dependent Claim
138 words
A signal routing device as claimed in claim 11 in which each of said, first, second, and third inductors has an inductance of from about 6 to about 10 microhenries, in which each of said first, second and third coupling capacitors has a capacitance of from about 500 to about 1,500 picofarads, and in which said first grounding capacitor has a capacitance of about 5 to 12 picofarads to provide a radiofrequency signal return loss of at least about 20 decibels at each of said first, second and third ones of said terminals over a radiofrequency range of from about 5 MHz to about 300 MHz with an isolation between said second and third ones of said terminals of at least about 25 decibels over said radio frequency range of from about 5 MHz to about 300 MHz.
Claim 16
Dependent Claim
180 words
A signal routing device as claimed in claim 13 in which each of said first, second and third inductors has and inductance of from about 6 to about 10 microhenries, in which each of said first, second and third coupling capacitors has a capacitance of from about 500 to about 1,500 picofarads, in which said first grounding capacitor has a capacitance of about 5 to 12 picofarads and in which said second grounding capacitor has a capacitance of at least about 0.005 microfarads to provide a radiofrequency signal return loss of at least about 20 decibels at each of said first, second and third ones of said terminals over a radiofrequency range of from about 5 MHz to about 300 MHz with an isolation between said second and third ones of said terminals of at least about 25 decibels over said radiofrequency range of from about 5 MHz to about 300 MHz and to permit the passage of alternating electrical current having a frequency of up to about 400 Hz between said first, second and third ones of said terminals.
Claim 17
Dependent Claim
53 words
A signal routing device as claimed in claim 11 in which each of said first, second and third inductors are interconnected as well as being connected to said base conductor through a second grounding capacitor to permit the passage of alternating electrical current between said first, second and third ones of said terminals.
Claim 18
Dependent Claim
79 words
A signal routing device as claimed in claim 15 in which each of said first, second and third inductors has an inductance of from about 6 to about 10 microhenries and in which each of said first, second and third coupling capacitors has a capacitance of from about 500 to about 1,500 picofarads to provide a radiofrequency signal return loss of at least about 25 decibels over said radiofrequency range of from about 5 MHz to about 300 MHz.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |