Patent US3790819A successfully refreshed from Google Patents.
US3790819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Log amplifier apparatus
Assignee: Bacharach Inc
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Filing: 1972-03-17
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Granted: 1974-02-05
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Expires: 1992-03-17
Abstract
Abstract An apparatus for increasing the stabilization of a logarithmic amplifier. In the embodiment disclosed, a first operational amplifier is provided to yield a logarithmic output. A semiconductor device for providing a first logarithmic transfer characteristic is connected to the first amplifier. In order to prevent variation in the amplifier output resulting from the varying parameters of the semi-conductor device, the second amplifier is provided with the semi-conductor device and connected differentially to the first amplifier. The semiconductor devices utilizes first and second PN junctions of semiconductor material mounted in intimate thermal coupling on a single header or alternatively utilizes a monolithic integrated circuit including a substrate of semiconductor material and means on the substrate for providing the logarithmic transfer characteristic for the first amplifier and means for the substrate for providing the logarithmic transfer characteristic for the second amplifier both deposited on the substrate in intimate thermal coupling with each other.
Inventors
- 👤 M Chamran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:06
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
290 words
In a logarithmic amplifying system comprising a first amplifier having an output terminal and an input terminal adapted to receive a first input signal having a first polarity and also comprising a first feedback network connected between the input terminal and the output terminal of the first amplifier so that the signal produced on the output terminal represents the logarithm of the first input signal, improved apparatus for stabilizing the signal produced on the output terminal comprising: a second amplifier having an input terminal and an output terminal; a second feedback network connected between the input terminal and the output terminal of the second amplifier; means for connecting the input terminal of the second amplifier to a source of predetermined reference voltage having a second polarity opposite the polarity of the first input signal; first semi-conductor means for providing a first logarithmic transfer characteristic having a predetermined polarity between a first output point and a second output point and second semiconductor means for providing a second logarithmic transfer characteristic having a predetermined polarity between a third output point and a fourth output point; means for connecting the first and second output points in the first feedback network and for connecting the third and fourth output points in the second feedback network so that the polarity of the first semi-conductor means in relation to the input and output terminals of the first amplifier is opposite the polarity of the second semi-conductor means in relation to the input and output terminals of the second amplifier; and means for algebraically summing the signals of opposite polarity conducted to the output terminals of the first and second amplifiers, whereby the opposed polarity of the first and second semi-conductor means stabilizes the summed output signal.
Claim 2
Dependent Claim
290 words
In a logarithmic amplifying system comprising a first amplifier having an output terminal and an input terminal adapted to receive a first input signal having a first polarity and also comprising a first feedback network connected between the input terminal and the output terminal of the first amplifier so that the signal produced on the output terminal represents the logarithm of the first input signal, improved apparatus for stabilizing the signal produced on the output terminal comprising: a second amplifier having an input terminal and an output terminal; a second feedback network connected between the input terminal and the output terminal of the second amplifier; means for connecting the input terminal of the second amplifier to a source of predetermined reference voltage having a second polarity opposite the polarity of the first input signal; first semi-conductor means for providing a first logarithmic transfer characteristic having a predetermined polarity between a first output point and a second output point and second semiconductor means for providing a second logarithmic transfer characteristic having a predetermined polarity between a third output point and a fourth output point; means for connecting the first and second output points in the first feedback network and for connecting the third and fourth output points in the second feedback network so that the polarity of the first semi-conductor means in relation to the input and output terminals of the first amplifier is opposite the polarity of the second semi-conductor means in relation to the input and output terminals of the second amplifier; and means for algebraically summing the signals of opposite polarity conducted to the output terminals of the first and second amplifiers, whereby the opposed polarity of the first and second semi-conductor means stabilizes the summed output signal.
Claim 3
Dependent Claim
27 words
Apparatus, as claimed in claim 1, and further comprising means for enclosing the semi-conductor means in intimate thermal coupling apart from the remaining components of the system.
Claim 4
Dependent Claim
91 words
Apparatus, as claimed in claim 1, wherein the semi-conductor means comprisEs: first means for forming a first PN junction of semi-conductor materials; second means for forming a second PN junction of semi-conductor materials; third means for mounting the first and second means on a single header in intimate thermal coupling; fourth means for electrically isolating the first means from the second means; fifth means for connecting the first means to the first and second output points; and sixth means for connecting the second means to the third and fourth output points.
Claim 5
Dependent Claim
82 words
Apparatus, as claimed in claim 3, wherein the fifth means comprises means for connecting the first means so that the first PN junction produces a voltage drop having a first predetermined polarity with respect to the input terminal of the first amplifier and wherein the sixth means comprises means for connecting the second means so that the second PN junction produces a voltage drop having a polarity opposite the first predetermined polarity with respect to the input terminal of the second amplifier.
Claim 6
Dependent Claim
16 words
Apparatus, as claimed in claim 3, wherein the first and second means each comprises a transistor.
Claim 7
Dependent Claim
77 words
Apparatus, as claimed in claim 1, wherein the semi-conductor means comprises: a monolithic integrated circuit comprising a substrate of semi-conductor material, first means formed on the substrate for providing said first logarithmic transfer characteristic and second means formed on the substrate for providing said second logarithmic transfer characteristic; third means for connecting the first means to the first and second output points; and fourth means for connecting the second means to the third and fourth output points.
Claim 8
Dependent Claim
27 words
Apparatus, as claimed in claim 6, and further comprising means for enclosing the semi-conductor means in intimate thermal coupling apart from the remaining components of the system.
Claim 9
Dependent Claim
83 words
Apparatus, as claimed in claim 1, and further comprising: second semi-conductor means for providing a third logarithmic transfer characteristic between a fifth output point and a sixth output point and for providing a fourth logarithmic transfer characteristic between a seventh output point and an eighth output point; means for connecting the fifth and sixth output points in series with the first and second output points; means for connecting the seventh and eighth output points in series with the third and fourth output points.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |