The determination of device noise parameters

Abstract

b: Fig. 1. (a) Basic circuit of subharmonic mcillator. (b) Ideal characteristic of nonlinear element.period of the output voltage waveform is 2r/wo seconds, so that if the second current step occurs r / w 0 seconds after the first, the two desaying sinusoids are directly in phase and therefore add. The cycle ABCDEDFBA is then repeated.Thus, in the steady state, an output oscillation is maintained across the tuned circuit by the periodic switching of current pulses from the nonlinear element. Detuning of the output circuit results in a reduction of amplitude of the output oscillation, but the output frequency is still of the formfi/n. By tuning the output to harmonics of the fundamental component of the current waveform, it is possible to generate frequencies which are rational fractions of the input frequency.Stable operation of the circuit with power gain is possible, power gain being defined as the ratio of the power developed at subharmonic frequency across the load resistance to the power flowing into the input terminals at the driving frequency. A further advantage of the circuit over other methods of subharmonic generation is its ability to produce high orders of frequency division. (An output frequency 1/2000Xthe input freqatvlcy has been obtained in practice.)The two circuits described below give fairly close approximations to the characteristic of Fig. lThe current-voltage characteristic of a tunnel diode can be considered to be composed of three sections, two with positive slope and one with negative s1ope:The effect of combining the tunnel diode with a resistor R in series is to increase the reciprocals of the slopes of the three sections by a value R. The approximation to the current-voltage characteristic of Fig. l(b) is obtained by setting the value of R greater than the inverse of the absolute value of the slope of the negative resistance section.The second configuration, presented in Fig. 2(a), is based on a circuit described by Ostefjellsl for the generation of a linear negative resistance. In the saturation and active regions of the matched transistors T I and T2, diodes D l and D 2 have no effect since they are reversebiased with their terminals open-circuited. In the cutoff region, when the current through RE is almost reduced to zero, resistors Rd are sufficient to forward-bias D l and Dz. Tl and T2 are now bypassed and current i flows through D l , &, Dfr and R. Fig. 2(b) shows the current-voltage characteristic of the circuit of Fig. 2(a). Rb provides a means of altering the value of u at which the active region ends by varying the voltage levels on one side of the diodes D I and D2 and thereby controlling the value of u at which the diodes become forward-biased. Rb is set to a value such that section BE of the transistors," Proc. fEEE(Correspondence). voI. 53, p. 404, April 1965. 1 S. Ostefplls, "Negative resistance circuit using two complementary field effect -/ d (b) Fig. 2. (a) Transistor-diode arcuit for generating nontinear characteristic. (b) Characteristic of the circuit in Fig. 2(...

Measurement Method of Noise Correlation Matrix Using Relative Noise Ratio

“…잡음 파라미터를 측정하는 통상적 인 방법으로는 NFA(Noise Figure Analyzer) [2], [3] . 최근에는 PNA-X 회로망 분석기 와 임피던스 튜너를 결합한 잡음 파라미터 측정 셋업이 발표된 바 있다 [4] .…”

A Novel Wide-Band Noise-Parameter Measurement Method and Its Cryogenic Application

“…The key point is the linearization of the noise temperature expression [5]. First, the noise temperature is expressed as a function of four noise parameters [6] (1) where is the generator reflection coefficient and is 290 K. The four noise parameters and complex are the minimum noise temperature, noise ratio, and optimum generator reflection coefficient, respectively.…”

Two Noise Parameter Measurement Methods Using Spectrum Analyzer and Comparison

“…잡 음 파라미터를 측정하는 통상적인 방법으로는 NFA(Noise Figure Analyzer) [2], [3] . 그러나 전통적인 이 방법은 고가이며, 임피던스 튜너의 조정으로 인해 상당한 계측시간을 요구하고, 또한, 온-웨이퍼(on-wafer) 측정에 상당한 제약을 준다.…”