Title:
Circuit arrangement comprising a logarithmic transfer function
Document Type and Number:
WIPO Patent Application WO1997033366
Kind Code:
A3
Abstract:
A circuit arrangement having a logarithmic transfer function between an input signal and an output signal in a predefined level range of the input signal circuit which has a very low power consumption and low circuit complexity, includes a first pair of amplifier elements, namely transistors, forming a first differential amplifier and a second pair of amplifier elements, namely transistors, forming a second differential amplifier. The first pair of transistors have their emitters connected to each other and to a first current source, their collectors connected to working impedances subdivided by respective taps, and their bases receive the input signal between them. The second pair of transistors have their emitters connected to each other and to a second current source, their collectors connected to the collectors of the first pair of transistors, respectively, and their bases cross-connected to the taps of the working impedances. A rectifier stage has inputs connected to the collectors of the first and second pairs of transistors and an output at which the output signal is formed.
Inventors:
DICK BURKHARD (NL)
Application Number:
PCT/IB1997/000200
Publication Date:
October 30, 1997
Filing Date:
March 05, 1997
Export Citation:
Assignee:
PHILIPS ELECTRONICS NV (NL)
PHILIPS PATENTVERWALTUNG (DE)
PHILIPS NORDEN AB (SE)
PHILIPS PATENTVERWALTUNG (DE)
PHILIPS NORDEN AB (SE)
International Classes:
G06G7/24; H03G11/08; H03F3/45; H03G7/00; (IPC1-7): H03G7/06
Foreign References:
| US5471166A | 1995-11-28 | |||
| EP0505751A2 | 1992-09-30 | |||
| EP0599399A1 | 1994-06-01 |
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