Electrical transmission or interconnection systems – Nonlinear reactor systems – Parametrons
Patent
1989-03-27
1991-02-05
Miller, Stanley D.
Electrical transmission or interconnection systems
Nonlinear reactor systems
Parametrons
307310, 3072966, 307491, 328145, G06F 7556, G06G 724, H03K 326
Patent
active
049908030
ABSTRACT:
A multi-stage logarithmic converter of the "successive-detection" or "progressive-compression" type including circuitry providing an accurate, temperature-stabilized logarithmic transfer function. The gain stages are DC-coupled throughout, though each also employs a demodulator comprising a full-wave rectifier, allowing operation in both baseband and demodulating modes. The signal path is differential and is balanced, including the demodulators. Each gain stage is based on a differential amplifier, or "long-tail pair" operated in an open-loop mode and biased by a tail current generator which supplies a tail current that is both proportional to absolute temperature and compensated automatically for effects of finite transistor beta and base and emitter resistances. The demodulators are biased by a very low offset voltage which also is proportional to absolute temperature. The log intercept is temperature-stabilized by either employing a PTAT attenuator ahead of the complete amplification system or by introducing at the output node (a current summing junction) a current which varies with temperature in such a way as to offset intercept movement which otherwise would be generated.
REFERENCES:
patent: 3435353 (1966-02-01), Sauber
patent: 3584232 (1971-06-01), Wallace, Jr.
patent: 3605027 (1971-09-01), Nichols
patent: 3668535 (1972-06-01), Lansdowne
patent: 4333023 (1982-06-01), Hood, Jr.
patent: 4565935 (1986-01-01), Rolfe
patent: 4604532 (1986-08-01), Gilbert
patent: 4724337 (1988-02-01), Maeda et al.
Analog Devices Inc.
Miller Stanley D.
Tran Toan
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