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Frequency Sweeping Phase/Amplitude Test Set

IP.com Disclosure Number: IPCOM000079707D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 50K

Publishing Venue

IBM

Related People

Comninos, R: AUTHOR

Abstract

The frequency-sweeping phase/amplitude test set 10 provides precision measurements of phase tracking to be performed on multichannel superheterodyne receivers, e.g., receiver 14, on a frequency-swept basis.

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Frequency Sweeping Phase/Amplitude Test Set

The frequency-sweeping phase/amplitude test set 10 provides precision measurements of phase tracking to be performed on multichannel superheterodyne receivers, e.g., receiver 14, on a frequency-swept basis.

The test data (phase difference vs. frequency) is produced as hard copy chart by recorder 11. The data can be used for exploratory testing of receivers or antenna-receiver combinations, and also for production testing for specification conformance. Amplitude versus frequency data is also produced. Frequency coverage may be as broad as that associated with the signal generator and the receiver under test. Time for testing is greatly reduced compared to manual spot frequency checks. The test set consists of commercially available standard laboratory equipment and devices. Lock circuitry 12 integrates and controls the overall operation.

In operation, sweep signal generator 13 provides the local oscillator range for the receiver 14 under test via a two-way power divider 15. The sweep signal generator is also routed via the two-way divider to an up converter 16. The up converter also receives an input at the receiver IF frequency from IF generator
17. The up converter 16 primarily produces an output at local output (LO) frequency and side bands LO +/- IF. These output frequencies are amplified by amplifier 18 and fed to YIG filter 19, Which filters out the desired side hand (LO + IF) or (LO - IF).

Filter 19 is tuned to the desired side band by lock circuitry 12 and offset power supply 20.

Lock circuitry 19 receives at differential amplifier 19a from generator 13 the sweep signal generator sweep voltage, which is an analog voltage proportional to the sweeper frequency (LO). Lock circuitry 19 converts signal generator scale factor (volts/MHZ) to the require...