Medical Humanities - BJSTR Journal

Abstract

Our recent investigations on mixers have been overviewed: Comparison,# microwave mixer design and adjustment of the conversion loss and the third order intercept point to any prescribed values. Goal of this overview paper is to introduce mixer circuits to a broader range of readers. Instead of obtaining a detailed review of literature, we start from definitions and qualitative operation. Then summary of a comparison of six diode and #six transistor mixers will follow. The most important Section is about investigation of possible limits of critical large signal properties. A mixer [2-4] is a three-port device. Technical terms like “port” are explained in [1]. A mixer has two input and one output ports. One of them is the RF (radio frequency) input, another one is the LO (local oscillator) input, and another one is the IF (intermediate frequency) output. Function of a #mixer in a more complex circuit environment like a radio, is to shift RF input frequency by the frequency of the LO to formulate IF. Down mixing means that the RF frequency is converted down into a much lower IF. This step is necessary because filtering can be more effective at lower frequency. In order to realize this function, the mixer should be nonlinear, time invariant [1] or linear, time variant [1]. The simplest linear, time variant circuit is a switch. In practice, both can be observed simultaneously. The difference between them is that IF signal of a nonlinear, time invariant circuit consists of infinite number of spectral lines, when the #nonlinearity is not polynomial, while that of a linear, time variant circuit contains only finite number of spectral lines.

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Anything Important That You Should Know About Mixers by János Ladvánszky in BJSTR