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Compact Modeling of SiGe HBTs: HICUM
Published in John D. Cressler, Measurement and Modeling of Silicon Heterestructure Devices, 2018
Noise figure NFmin and equivalent noise resistance Rn versus frequency are shown in Figure 6.8 for a 150 GHz production process. The bias point is typical for low-noise applications. HICUM gives good agreement for Rn over the whole frequency range and for NFmin at high frequencies. The observable deviation at lower frequencies is caused by the missing correlation between collector and base noise, which has not yet been implemented in circuit simulators. This is confirmed by the thin line that results from a HICUM-generated small-signal model (SSM) with added correlation.
Active and Diversity Receiving Antenna Systems
Published in Victor Rabinovich, Nikolai Alexandrov, Basim Alkhateeb, Automotive Antenna Design and Applications, 2010
Victor Rabinovich, Nikolai Alexandrov, Basim Alkhateeb
Fmin, Γopt, and Rn (equivalent noise resistance of a transistor) are generally specified in the transistor data sheet. Therefore, by choosing different ΓS values, we can control the value of the noise at the amplifier output. When ΓS = Γopt, the noise figure value Famp is minimal and equal to Fmin. If we lack such data for noise optimization, we may use a noise figure meter to find the optimal value experimentally.
Noise Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
A mean-square noise voltage can be represented in terms of an equivalent noise resistance [8]. Let vn2¯ be the mean-square noise voltage in the band Δf. The noise resistance Rn is defined as the value of a resistor at the standard temperature T0 = 290 K that generates the same noise. It is given by
Added Noise in Oscillators Caused by the Transistor Base Emitter Breakdown Phenomenon
Published in IETE Journal of Research, 2023
Wolfgang Griebel, Matthias Rudolph, Ulrich L. Rohde
It uses feedback system with an active device, a mixer, a resonator, and various noise sources. The principal formula was derived by D. Leeson [4], D. Scherer [5] added the flicker noise term, J. Everard [6] introduced the loaded Q and Rohde extended the formula with a voltage-controlled oscillator (VCO) component [7]: where L (fm) is the ratio of sideband power in a 1 Hz bandwidth at fm to total power in dB; fm is the frequency offset; f0 is the center frequency; fc is the flicker corner frequency; QL is the loaded Q of the tuned circuit; F is the noise factor; k is the Boltzmann’s constant (1.38*10−23 J/K); T is the oscillator temperature (300 K assumed); Psav is the average oscillator power output (W); R is the equivalent noise resistance of tuning diode (typically 50 Ω–10 kΩ); Ko is the oscillator voltage gain, MHz/V (typically a few 100mHz/V for an HF USO).
Electrochemical noise of a Li-ion battery during the charging process
Published in Instrumentation Science & Technology, 2020
The length of the data array was 30000 points. Power spectral density (PSD) frequency dependencies were calculated using the averaging factor of 30 with a single segment length of 1000 points. Linear trend removal procedure was used to remove the low-frequency drift.[25,26] This procedure was tested in several works with different types of chemical power sources.[27,28] The Nyquist equation[29] was used to recalculate ECN PSD spectra in to equivalent noise resistance. It is possible to plot these spectra in the same coordinates with the thermal noise frequency dependences after that. The thermal noise spectra are represented by the real part of electrochemical impedance frequency dependencies for the batteries.[30]
Electrochemical noise measurement methodologies of chemical power sources
Published in Instrumentation Science & Technology, 2018
The last circuit (Figure 1(f)) requires two identical batteries under test. The main limitation is that it is impossible to use on a single object. It can also raise a lot of potential problems during the discharge of two batteries because the load voltages can change asynchronously. The main advantages of this circuit are that it is not limited in the low frequency range, and in case of identical batteries, the measured voltage amplitude is increased in square root of 2. In terms of equivalent noise resistance, it is doubled as the impedance is doubled.