A Medium Power Traveling-Wave Tube for 6,000-Mc Radio Relay

Laico, J. P.; McDowell, H.L.; Moster, C. R.

doi:10.1002/j.1538-7305.1956.tb03831.x

Cited by 44 publications

(5 citation statements)

References 8 publications

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“…The technique used to make the measurements was adapted from a technique used to measure tine AM-PM Conversion of traveliny-wave tubes (ref. 4). The ulock diayra,l of the instrumentation is identical to that used for the third-order intermuuulation tests 1Fig.…”

Section: Rani Lituae R^loaulation -Phasementioning

confidence: 99%

Testing of 30-GHz low noise receivers

Conroy

Kerczewski²

1986

11th Communications Satellite Systems Conference

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NASA-Lewis sponsored studies of tree growth in conlnuniCations traffic have indicated that the frequency spectrum allocatea to fixed-service satellites at the C ana Ku bands will reach saturation uy the early 1990's. The next nigher frequency Dands allocated fo r coinnunications satellites are el., to 30 GHz for the uplink and 11.1 to eU.e GHz for the downlink. Current plans for oevelupiny satellite systems that use these bands i tic Iuoe a NASA demonstration satellite (ALTS). Une of tilt Loin p onents identified as critical to the SuCCt,s of that mission is a 21.5 to 30 GHz satellite receiver.in response to that identification, NASA has sponsored the development of such a receiver to ore prouf-of-concept (PUC) level. Design and faoricatlon of such POC model receivers was carried out under parallel contracts awarded to LNR CuumiunlCdtions, Inc. of Hauppauye, New York and to ITT Defense Loianunications Division of Nutley, New Jersey. Tne most significant of the performance goals were a 5 dB maximum noise figure, a 2.o uHz passoand, and 20 dB RF to IF gain.Following delivery of naroware from each of the cuntrdCtors, an in-house test program was undertaken at NASA Lewis in order to verify thê _ontrdctor-reported performance and to provide a cumparison of the two receivers under identical test conditions. The present paper reports the results of those tests.

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Section: Rani Lituae R^loaulation -Phasementioning

confidence: 99%

Testing of 30-GHz low noise receivers

Conroy

Kerczewski²

1986

11th Communications Satellite Systems Conference

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“…There is a very good agreement with expected values, and measurements are very reproducible. The derivative of the curves were compared to Kp measurements, they are much smoother and more reproducible than those obtained with the Bell method ([1]) as it can be seen on figure 4.…”

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confidence: 99%

In orbit phase shift measurement on a satellite transponder

Belfort

Guieysse

Lermoyer

1993

23rd European Microwave Conference, 1993

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Due both to frequency down conversion on board geostationary communication satellites and Doppler effect, phase shift versus input drive had never been directly measured in orbit. For TELECOM 2 in orbit test, we conceived a new method and set up a test bench to perform this measurement. This method is based on the cancellation of the frequency offsets mentioned above. Results obtained on TELECOM 2A and 2B are in good agreement with the expected values and this method improves greatly the accuracy and reproducibility of the Kp factor measurement.

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“…This is an adequate assumption for most power amplifiers operated with sufficiently narrowband input signals, i.e., where the signal bandwidth is much less than the component bandwidth as measured by a VNA. However, in some instances this assumption is violated even for "narrowband" signals i n both SSPAs (63) and TWTAs (64) due to both dc bias circuit resonances and thermal effects. To find the dynamic gain and phase transfer curves, one can use an input signal to the nonlinear component that has a small amount of periodic AM induced upon it.…”

Section: Dynamic Am/am and Am/pm Measurement Techniques Using A Periomentioning

confidence: 99%

“…In a second implementation of this concept (11,64) the input AM is induced not by directly modulating the carrier, but rather by adding to it a small tone, offset from it by That is, the input signal is An advantage of this implementation is that the phase of the input or output signal need not be measured directly. One can obtain the AM/AM and AM/PM solely from amplitude measurements.…”

Section: Dynamic Am/am and Am/pm Measurement Techniques Using A Periomentioning

confidence: 99%

Modeling and Simulation of Nonlinear Systems

Simulation of Communication Systems

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Perhaps the single greatest justification for the simulation approach to the study of communication systems is the presence of nonlinear elements. In principle, the performance of linear systems can be attacked by analytical means, but the study of nonlinear systems by such means is by and large intractable. Although there have been many analytical studies of one or another nonlinear device, the system context is usually idealized or much simplified compared to realistic scenarios. In addition, it is typical for such analytical formulations to be of such complexity as to require numerical evaluation, a situation which negates the values of analysis-insight and generality. Hence, simulation is generally the appropriate tool for perhaps most nonlinear communication systems because simulation of such systems is no more difficult than for linear systems, given the model. Indeed, the main difficulty i n nonlinear system simulation is obtaining the model itself. Hence, much of the focus in this chapter will be on modeling methodology and on associated measuring techniques for determining parameters of models.In general, a nonlinear system consists of linear and nonlinear elements. Some of the linear elements may be described by linear differential equations, as discussed in the previous chapter, or by other relationships. The nonlinear elements, which are normally relatively few in number, are described by nonlinear functions or nonlinear differential equations relating the input and output of the element. The transform methods described in the previous chapters cannot strictly be applied to nonlinear systems since superposition does not hold in the latter case. The nonlinear system, therefore, generally has to be simulated in the time domain. This applies to the nonlinear part of the system only. The rest of the system can be simulated either in the time domain or the frequency domain (see Figure 5.1), except when it is part of a feedback system. In contrasting linear and nonlinear system simulation, we should make another point. In the linear case, we are generally satified that we will tend to the correct answer under certain limiting conditions (assuming no finite-precision effects), such as letting the sampling interval become smaller and smaller or increasing the duration of a (truncated) finite impulse response. In nonlinear systems, there is no clear set of limiting conditions under which we can assert that the model comes closer to reality, because it is so much more difficult to ascertain the closeness of a nonlinear model to the functioning of the actual device. This reenforces the point made in Chapter 2 about the need to validate simulation models against hardware counterparts. 203 204 Chapter 5 Figure 5.1. Simulation of a nonlinear communication system. Modeling Considerations for Nonlinear SystemsUsually devices used in communication systems such as traveling-wave tube amplifiers (TWTAs) and solid-state power amplifiers (SSPAs) are described by analytical models that typically involve solving a set of si...

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A Medium Power Traveling-Wave Tube for 6,000-Mc Radio Relay

Abstract: This paper discusses a traveling‐wave amplifier which gives 30 db of gain at 5 watts output in the 5,925‐ to 6,425‐mc common carrier band. A description of the tube and detailed performance data are given.

Cited by 44 publications

References 8 publications

Testing of 30-GHz low noise receivers

Testing of 30-GHz low noise receivers

In orbit phase shift measurement on a satellite transponder

Modeling and Simulation of Nonlinear Systems

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