Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – Frequency of cyclic current or voltage
Patent
1986-12-01
1989-03-14
Pellinen, A. D.
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
Frequency of cyclic current or voltage
375 10, G01R 2704
Patent
active
048127388
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an apparatus for analyzing transmission/reflection characteristics, which can measure both transmission/reflection characteristics with the use of a 2-channel heterodyne type level measuring device.
BACKGROUND ART
FIG. 1 is a block diagram showing a conventional reflection characteristic measuring apparatus with the use of a spectrum analyzer. Upon the receipt of an output signal from a tracking generator 2 of synchronous transmitter type, reflection signal separator 3 allows a reflection signal from a to-be-measured object, e.g.) circuit network 4 to be supplied to spectrum analyzer 1 which is comprised of a 1-channel heterodyne receiver. Reflection signal separator 3 is called an impedance bridge.
As shown in FIG. 1, the output signal of tracking generator 2 is coupled to reflection signal separator 3, and circuit network 4 is connected to a measuring terminal side of reflection signal separator 3 so that a reflection signal from circuit network 4 is separated by separator 3 and supplied to an input terminal of spectrum analyzer 1. In this way, it is possible to measure the reflection characteristic. Here it is to be noted that circuit network 4 terminates in reflectionless terminating device 5.
FIG. 2 is a block diagram for measuring the transmission characteristic of circuit network 4. This measuring circuit is comprised of tracking generator 2 and circuit network 4 to measure the transmission characteristic in circuit network 4.
In the method for measuring the aforementioned transmission/reflection characteristics using the spectrum analyzer as shown in FIGS. 1 and 2, the transmission and reflection characteristics cannot simultaneously be measured due to only one channel being present at the input of the spectrum analyzer. Furthermore, if a measuring signal is switched by a switching device to measure both the transmission and reflection signals, then no exact result of measurement can be obtained due to a variation in the reproducibility of the switching device and in the condition of matching.
DISCLOSURE OF INVENTION
It is accordingly the object of this invention to provide an apparatus for analyzing transmission/reflection characteristics, which can simultaneously measure both transmission and reflection characteristics without switching of connections.
In order to attain the aforementioned object an apparatus is provided which analyzes transmission/reflection characteristics. This apparatus comprises:
a signal generator for measurement which generates a measuring signal whose frequencies sequentially varies with time;
a reflection signal separator having an input port supplied with the measuring signal, a test port and an output port;
a through transmission path and short- and open-circuiting elements selectively connected to the test port;
a first heterodyne receiver having a receiving terminal connected to the output port;
a second heterodyne receiver having a receiving terminal connected to the through transmission path;
a first memory circuit for storing an output signal of the second heterodyne receiver in association with the frequency of the measuring signal when the second heterodyne receiver is connected to the test port via the through transmission path;
a second memory circuit for storing the output signal of the first heterodyne receiver in association with the frequency of the measuring signal when the short-circuiting element is connected to the test port;
a third memory circuit for storing the output signal of the first heterodyne receiver when the open-circuiting element is connected to the test port;
an arithmetic operation device for calibrating the output signals of the first and second heterodyne receivers with the use of memory contents of the first to third memory circuits when an object to be measured is connected between the output port and the second heterodyne receiver; and
a device for allowing the output signals of the first and second heterodyne receivers which have been calibrated by the arithmetic operation device to
REFERENCES:
patent: 3197696 (1965-07-01), Bibo
patent: 4349707 (1982-09-01), Perrigault et al.
Anritsu Catalog-Network/Spectrum Analyzer-Model MS620J, Dec. 1985.
Itaya Hiroshi
Saito Goro
Anritsu Corporation
Ginsburg Morris
Pellinen A. D.
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