US4374363A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Balanced impedance coupler
Assignee: Individual
•
Filing: 1980-11-03
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Granted: 1983-02-15
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Expires: 2000-11-03
Abstract
Abstract A balanced preamplifier is disclosed for impedance-coupling an audio signal source, such as a microphone, to a differential amplifier. In one embodiment, the preamplifier comprises a first stage wherein a pair of complementary bipolar transistors are connected in a common-base configuration and coupled to a low-impedance microphone so that the microphone signal is appied to the respective emitters of the transistors and transformed to an appropriately higher impedance level at the respective collectors thereof with common-mode passage of external and internal noise. A second stage including a complementary pair of bipolar transistors in a common-emitter configuration is coupled to the first stage for greater power and voltage amplification requirements. In a second embodiment, the preamplifier comprises a pair of complementary field-effect transistors (FET) connected in a series common-drain configuration and coupled to a high-impedance microphone so that the microphone signal is applied to the respective gates of the FETs and transformed to an appropriately lower impedance level at the respective sources thereof with common-mode passage of noise.
Inventors
- 👤 Frank R. Previti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:38
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/26; H03F1/00; H03F1/56
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
55 words
A circuit for coupling a two-terminal signal source of low impedance to a differential processor having a two-terminal input of higher impedance, comprising: a first pair of complementary bipolar transistors arranged in a common-base configuration having a balanced input directly across the respective emitters of said transistors and a balanced output across the respective collectors.
Claim 2
Dependent Claim
55 words
A circuit for coupling a two-terminal signal source of low impedance to a differential processor having a two-terminal input of higher impedance, comprising: a first pair of complementary bipolar transistors arranged in a common-base configuration having a balanced input directly across the respective emitters of said transistors and a balanced output across the respective collectors.
Claim 3
Dependent Claim
62 words
An impedance-coupling circuit according to claim 1, further comprising: a second pair of complementary bipolar transistors arranged in a common-emitter configuration and directly coupled to the output of said first pair of transistors to increase the power and voltage amplification, said second pair of transistors having a balanced input across the respective bases thereof and a balanced output across the respective collectors.
Claim 4
Dependent Claim
57 words
A circuit for coupling a two-terminal signal generator of high impedance to a differential processor having a two-terminal input of lower impedance, comprising: a pair of complementary field-effect transistors arranged in a common-drain configuration having a balanced input directly across the respective gates of said transistors and a balanced output across the respective sources of said transistors.
Claim 5
Dependent Claim
57 words
A circuit for coupling a two-terminal signal generator of high impedance to a differential processor having a two-terminal input of lower impedance, comprising: a pair of complementary field-effect transistors arranged in a common-drain configuration having a balanced input directly across the respective gates of said transistors and a balanced output across the respective sources of said transistors.
Claim 6
Dependent Claim
56 words
An audio preamplifier for coupling a low impedance microphone having two output terminals to a higher impedance differential amplifier having two input terminals, comprising: a first pair of complementary bipolar transistors arranged in a common-base configuration having a balanced input directly across the respective emitters of said transistors and a balanced output across the respective collectors.
Claim 7
Dependent Claim
56 words
An audio preamplifier for coupling a low impedance microphone having two output terminals to a higher impedance differential amplifier having two input terminals, comprising: a first pair of complementary bipolar transistors arranged in a common-base configuration having a balanced input directly across the respective emitters of said transistors and a balanced output across the respective collectors.
Claim 8
Dependent Claim
62 words
An audio preamplifier according to claim 4, further comprising: a second pair of complementary bipolar transistors arranged in a common-emitter configuration and directly coupled to the output of said first pair of transistors to increase the power and voltage amplification, said second pair of transistors having a balanced input across the respective bases thereof and a balanced output across the respective collectors.
Claim 9
Dependent Claim
57 words
An audio preamplifier for coupling a high impedance microphone having two output terminals to a lower impedance differential amplifier having two input terminals, comprising: a pair of complementary field-effect transistors arranged in a common-drain configuration having a balanced input directly across the respective gates of said transistors and a balanced output across the respective sources of transistors.
Claim 10
Dependent Claim
57 words
An audio preamplifier for coupling a high impedance microphone having two output terminals to a lower impedance differential amplifier having two input terminals, comprising: a pair of complementary field-effect transistors arranged in a common-drain configuration having a balanced input directly across the respective gates of said transistors and a balanced output across the respective sources of transistors.
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) | 1986-02-14 | 1986-08-16 | 1987-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-14 | 1990-08-16 | 1991-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-14 | 1994-08-16 | 1995-02-15 | $7700.00 | Window Closed / Lapsed |