US3614668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double-balanced modulators of the current switching type
Assignee: NEC Corp
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Filing: 1970-02-13
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Granted: 1971-10-19
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Expires: 1990-02-13
Abstract
Abstract A double-balanced modulator for modulating a carrier with an input signal. A pair of balanced amplifiers each are arranged to modulate a carrier signal with an input signal during alternating half-wave periods of the carrier. The input signal is coupled to the pair of balanced amplifier-modulators by means of a constant current driver circuit which applies operating current in alternating fashion to the pair of balanced amplifier-modulators whereby only that modulator which is operating during any given half cycle receives operating current so as to produce a modulated carrier which is substantially free of unwanted harmonics and is therefore substantially distortion-free.
Inventors
- 👤 Toshiaki Sudoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:38
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/38; H03C3/40; H03C1/00; H03C1/52; H03C1/54; H03C1/542; H03C1/545
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
184 words
In a double-balanced modulator having first and second balanced amplifiers each having first and second input terminals and first and second output terminals and a control terminal; said balanced amplifiers being connected in parallel whereby the first input terminals, the second input terminals, the first output terminals and the second output terminals of said first and second balanced amplifiers are respectively connnected in common, whereby the polarities of their outputs are mutually reversed; means for coupling a carrier signal across the control terminals of said first and second balanced amplifiers to operate the balanced amplifiers in a one at a time alternating fashion; input means for simultaneously coupling a signal to be modulated to the first and second input terminals of both of said balanced amplifiers; output means connected to the first and second outputs of both of said balanced amplifiers for alternately extracting the modulated signal for the balanced amplifiers the improvement comprising constant current driving means connected between said input means and the first and second input terminals of both of said balanced amplifiers for maintaining uniform current in said balanced amplifiers.
Claim 2
Dependent Claim
184 words
In a double-balanced modulator having first and second balanced amplifiers each having first and second input terminals and first and second output terminals and a control terminal; said balanced amplifiers being connected in parallel whereby the first input terminals, the second input terminals, the first output terminals and the second output terminals of said first and second balanced amplifiers are respectively connnected in common, whereby the polarities of their outputs are mutually reversed; means for coupling a carrier signal across the control terminals of said first and second balanced amplifiers to operate the balanced amplifiers in a one at a time alternating fashion; input means for simultaneously coupling a signal to be modulated to the first and second input terminals of both of said balanced amplifiers; output means connected to the first and second outputs of both of said balanced amplifiers for alternately extracting the modulated signal for the balanced amplifiers the improvement comprising constant current driving means connected between said input means and the first and second input terminals of both of said balanced amplifiers for maintaining uniform current in said balanced amplifiers.
Claim 3
Dependent Claim
37 words
The modulator of claim 1 wherein said constant current driving means is comprised of first and second constant driving circuits for respectively supplying uniform current to the first and second inputs of both of said balanced amplifiers.
Claim 4
Dependent Claim
39 words
A modulator as claimed in claim 1, wherein at least one of said constant current driving circuits deliver, in response to said signal to be modulated, balanced outputs which are substantially equal in magnitude and are of opposite polarity.
Claim 5
Dependent Claim
22 words
A modulator as claimed in claim 1, in which at least one of said constant current driving circuits is a differential amplifier.
Claim 6
Dependent Claim
18 words
A modulator as claimed in claim 4 in which said carrier signal input means is a differential amplifier.
Claim 7
Dependent Claim
16 words
A modulator as claimed in claim 4 in which said output means is a differential amplifier.
Claim 8
Dependent Claim
43 words
A modulator as claimed in claim 2 wherein said input means is comprised of a transformer having an input winding for receiving the input signal and a symmetrical output winding coupled to the inputs of said first and second constant current driving circuits.
Claim 9
Dependent Claim
46 words
A modulator as claimed in claim 2 wherein said means for coupling said carrier signal is comprised of a transformer having an input winding for receiving the carrier signal and a symmetrical output winding coupled to the control terminals of said first and second balanced amplifiers.
Claim 10
Dependent Claim
51 words
A modulator as claimed in claim 2 wherein said output means is comprised of a transformer having a symmetrical input winding for alternately receiving the modulated output from the first and second output terminals of said first and second balanced amplifiers; and an output winding for developing the final modulated signal.
Claim 11
Dependent Claim
90 words
The modulatOr of claim 1 wherein each balanced amplifier is comprised of first and second transistors having base, emitter and collector electrodes; the first and second input terminals of each balanced amplifier being respectively connected to the emitter electrodes of said first and second transistors, the control terminal of each balanced amplifier being connected in common to the base electrodes of said first and second transistors; and the first and second output terminals of each balanced amplifier being respectively connected to the collector electrodes of said first and second 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) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |