Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
183 words
A logarithmic converter for supplying in response to an instantaneous input signal an output signal representing a corresponding logarithmic value thereof, the performance of the converter being characterized at least in part by a log intercept value and by a log slope, and comprising: a. a plurality of gain stages, each having (i) a transistor amplifier which has an input and an output, and (ii) a full-wave detector having an input and an output, the input of the full-wave detector being connected to receive the output of the transistor amplifier; b. a first one of the amplifiers being connected to receive at its input the input signal; c. each other amplifier being connected to receive at its input the output from another one of the amplifiers; d. the full-wave detectors each supplying a current output and the current outputs of all of the detectors being summed to provide the converter's output; and e. stabilization means operatively associated with each amplifier to cause the gain of the amplifier to be substantially insensitive to temperature variations and variations in production tolerances of the amplifier transistors.
Claim 2
Dependent Claim
183 words
A logarithmic converter for supplying in response to an instantaneous input signal an output signal representing a corresponding logarithmic value thereof, the performance of the converter being characterized at least in part by a log intercept value and by a log slope, and comprising: a. a plurality of gain stages, each having (i) a transistor amplifier which has an input and an output, and (ii) a full-wave detector having an input and an output, the input of the full-wave detector being connected to receive the output of the transistor amplifier; b. a first one of the amplifiers being connected to receive at its input the input signal; c. each other amplifier being connected to receive at its input the output from another one of the amplifiers; d. the full-wave detectors each supplying a current output and the current outputs of all of the detectors being summed to provide the converter's output; and e. stabilization means operatively associated with each amplifier to cause the gain of the amplifier to be substantially insensitive to temperature variations and variations in production tolerances of the amplifier transistors.
Claim 3
Dependent Claim
42 words
The logarithmic converter of claim 1, wherein the transistor amplifiers are differential amplifiers biased by a tail current and wherein the stabilization means includes means for generating a tail current for each amplifier, which tail current is substantially proportional to absolute temperature.
Claim 4
Dependent Claim
37 words
The logarithmic converter of claim 2 wherein the means for generating the tail current is adapted to provide a tail current which is a function of the current gain of the amplifier transistors and their intrinsic resistances.
Claim 5
Dependent Claim
27 words
The logarithmic converter of any of claims 1-3 further including means for compensating for the temperature dependence of the detector output currents, to stabilize the log intercept.
Claim 6
Dependent Claim
33 words
The logarithmic converter of claim 4 wherein the means for compensating includes an attenuator at the input of the first amplifier, said attenuator providing an attenuation factor which is proportional to absolute temperature.
Claim 7
Dependent Claim
35 words
The logarithmic converter of claim 4 wherein the means for compensating includes means for combining with the summed detector output currents a current which compensates for changes in the summed current with variations in temperature.