US5448188A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal processing device for providing a signal corresponding to an input signal and for providing a signal which does not correspond to the input signal
Assignee: Fujifilm Corp
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Filing: 1994-04-04
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Granted: 1995-09-05
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Expires: 2014-04-04
Abstract
Abstract A signal processing device for selectively producing as an output signal either a signal corresponding to an input signal r a signal which may be a fixed voltage level for muting purposes or a mixed signal. A current switch composed of pairs of differential transistors switches Among a plurality of current paths in accordance with a difference between the voltage levels of a pair of input signals varying in level in phase opposition to each other, or in accordance with a difference between the voltage levels of a reference voltage and a signal phase input signal. A load circuit composed of a plurality of resistors is connected in series with one of the current paths. A current bypass forming circuit which forms a current bypass of a constant current at a desired timing corresponding to a pulse signal with respect to the current path forming the load circuit effects the generation of an output signal not corresponding to the input signal, that is, a fixed voltage for muting the mixed signal.
Inventors
- 👤 Motoaki Matsumoto
- 👤 Yoshihiko Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:20
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/222; H04N5/262; H04N5/265; H03; H03F; H03F3/00; H03F3/72; H04N5/44; H04N5/445
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
156 words
A signal processing device comprising: a differential amplifier comprising first and second transistors connected in respective first and second current paths, and a first constant current source connected to said first and second transistors; a source of a pair of input signals, the input signals being applied to said first and second transistors, respectively; a load circuit connected in said second current path; and a current bypass circuit for bypassing current from said second current path, and having a switch for selectively coupling said current bypass circuit to said second current path, wherein said load circuit comprises a pair of resistors having equal resistance values and being connected in series with one another in said second current path, wherein said current bypass circuit is connected to a connection point between said resistors, and an output terminal of said signal processing device is connected to a connection point between one of said resistors and said second transistor.
Claim 2
Dependent Claim
156 words
A signal processing device comprising: a differential amplifier comprising first and second transistors connected in respective first and second current paths, and a first constant current source connected to said first and second transistors; a source of a pair of input signals, the input signals being applied to said first and second transistors, respectively; a load circuit connected in said second current path; and a current bypass circuit for bypassing current from said second current path, and having a switch for selectively coupling said current bypass circuit to said second current path, wherein said load circuit comprises a pair of resistors having equal resistance values and being connected in series with one another in said second current path, wherein said current bypass circuit is connected to a connection point between said resistors, and an output terminal of said signal processing device is connected to a connection point between one of said resistors and said second transistor.
Claim 3
Dependent Claim
31 words
The signal processing device of claim 1, wherein said current bypass circuit comprises a second constant current source and a transistor switch connected in series with said second constant current source.
Claim 4
Dependent Claim
31 words
The signal processing device of claim 1, wherein said switch of said current bypass circuit comprises a transistor switch connected between said second current path and said first constant current source.
Claim 5
Dependent Claim
54 words
The signal processing device of claim 3, further comprising an output transistor and a second constant current source connected in an emitter follower circuit, a base of said output transistor being connected to said load circuit, and an output terminal of said signal processing device being connected to an emitter of said output transistor.
Claim 6
Dependent Claim
40 words
The signal processing device of claim 3, wherein said transistor switch comprises a double-emitter transistor having a collector connected to said load circuit and a pair of emitters connected to emitters of respective ones of said first and second transistors.
Claim 7
Dependent Claim
31 words
The signal processing device of claim 3, wherein said transistor switch comprises a transistor having a collector connected to said load circuit and an emitter connected to said first current source.
Claim 8
Dependent Claim
28 words
The signal processing device of claim 1, wherein said input signals comprise a pair of signals varying in level 180° out of phase with respect to one another.
Claim 9
Dependent Claim
20 words
The signal processing device of claim 1, wherein said input signals comprise a reference voltage and a single-phase input signal.
Claim 10
Dependent Claim
34 words
The signal processing device of claim 8, wherein said reference voltage is applied to a base of said second transistor, and said single-phase input signal is applied to a base of said first transistor.
Claim 11
Dependent Claim
80 words
The signal processing circuit of claim 1, wherein said bypass circuit further comprises: a second differential amplifier comprising third and fourth transistors and a third constant current source connected to said third and fourth transistors; a reference voltage source connected to bases of said second and third transistors; and a fifth transistor connected in parallel to said first transistor, wherein a control signal is applied to bases of said fourth and fifth transistors to select between normal and muting operations.
Claim 12
Dependent Claim
128 words
The signal processing circuit of claim 4, further comprising a second differential amplifier comprising third and fourth transistors and a third constant current source connected to said third and fourth transistors; a fifth transistor connected in parallel to said first transistor; a sixth transistor connected between said load circuit and said third current source; and a reference voltage source connected to a base of said third transistor, wherein said input signals comprise a pair of signals varying in level 180° out of phase with respect to one another, a control signal is applied to bases of said fifth and sixth transistors to select between normal and muting operations, and a signal to be superimposed on said output signal is being applied to a base of said fourth transistor.
Claim 13
Dependent Claim
87 words
The signal processing device of claim 4, wherein said bypass circuit further comprises third and fourth transistors connected between said load circuit and said first constant current source, wherein said input signals comprise a pair of signals varying in level 180° out of phase with respect to one another, a control signal is applied to a base of said third transistor to select between normal and muting operations, and a signal to be superimposed on said output signal is applied to a base of said fourth transistor.
Claim 14
Dependent Claim
76 words
The signal processing device of claim 12, wherein said load circuit comprises first through third resistors connected in series with one another, in the order stated, between a power source terminal and a collector of said second transistor, a collector of said third transistor is connected to a connection point between said first and second resistors, and wherein a collector of said fourth transistor is connected to a connection point between said second and third resistors.
Claim 15
Dependent Claim
75 words
The signal processing circuit of claim 4, further comprising: a second differential amplifier comprising third and fourth transistors and a third constant current source connected to said third and fourth transistors; a reference voltage source connected to a base of said third transistor; and a fifth transistor connected in parallel to said first transistor, wherein a control signal is applied to bases of said fourth and fifth transistors to select between normal and muting operations.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-09-04 | 1999-03-06 | 1999-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-04 | 2003-03-06 | 2003-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-04 | 2007-03-06 | 2007-09-05 | $7700.00 | Window Closed / Lapsed |