Browse Prior Art Database

Wide Band Comb Generator

IP.com Disclosure Number: IPCOM000085873D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Grabala, CJ: AUTHOR

Abstract

One way of measuring the bandwidth of an amplifier is to apply different frequencies from a RF sweep generator to the amplifier to be tested, and observing or plotting the amplifier outputs to determine the bandwidth of the amplifier.

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Wide Band Comb Generator

One way of measuring the bandwidth of an amplifier is to apply different frequencies from a RF sweep generator to the amplifier to be tested, and observing or plotting the amplifier outputs to determine the bandwidth of the amplifier.

This alternate circuit approach to measuring the bandwidth of an amplifier consists of using a single frequency RF generator 10 as depicted in Fig. 1. This single RF frequency signal is fed to a dual-diode harmonic generator network 12, which generates a harmonic comb produced by the nonlinear action of RF on the diodes.

The step recovery diodes D1 and D2 used have a fast transition time, which allows full usage of the forward stored charge effect in improving nonlinearity and efficiency for harmonic generation. The output level is -60 DB from the input which makes it an ideal low-level, wide-band amplifier signal source. Resistors R1, R2 and R3 shown in the dual-diode harmonic generator schematic, Fig. 2, are used to match transmission line impedances.

The frequency of the RF input generator 10 is independent of the circuit and is at the discretion of the user. In Fig. 1 the signal frequency is shown as 2.5 MHZ. The diodes D1 and D2 are Hewlett Packard -5082-0112 step recovery diodes. The output of the dual-diode harmonic generator is fed to the amplifier under test 14. The output of the amplifier 14 can be viewed on a spectrum analyzer 16, wherein the instantaneous bandwidth of the amplifier 14 can be easi...