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Base To Peak Amplitude Detector

IP.com Disclosure Number: IPCOM000080384D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Nielsen, CR: AUTHOR

Abstract

Transistors Q2 and Q3 form a differential amplifier for switching the current from current source Q1. Transistor switches Q5 and Q6 direct the current output from the current source Q4. An integrator is formed by resistors R3 and C1. The output of the integrator is fed into a voltage follower OA1 for impedance matching.

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Base To Peak Amplitude Detector

Transistors Q2 and Q3 form a differential amplifier for switching the current from current source Q1. Transistor switches Q5 and Q6 direct the current output from the current source Q4. An integrator is formed by resistors R3 and C1. The output of the integrator is fed into a voltage follower OA1 for impedance matching.

In operation the AC signal is differentially inputted to the input of transistors Q2 and Q3, causing the transistor having the most position input to be in conduction at any given instant of time. Current for Q4 is used to charge capacitor C1 through transistor switch Q6. Transistor switch Q6 is turned on whenever there is an output from Q2. transistor Q3. This allows the constant-current source Q4 to be operative at all times and, therefore, does not introduce any transients due to any unloading of the current source Q4.

The voltage on capacitor C1 is passed through the operational amplifier, which acts as a voltage follower to isolate C1 from the rest of the circuit. The output of the voltage amplifier is the voltage across capacitor C1. The output voltage is fed back as a DC reference voltage to transistor Q3 in the differential amplifier.

When the reference voltage on capacitor C1 is equal to the maximum value of the voltage of the positive half-cycle being inputted to transistor Q2, the differential amplifier will not be able to switch. The differential amplifier will be in a state such that Q3 will be in condu...