The stability of current source with feedback loop outperforms the current source without feedback loop for resistive and capacitive loads in simulation. The output impedance of current source with feedback loop is greater than the one without feedback loop. The output performance of this current source is evaluated by simulation and actual measurement. New features of the proposed multi-frequency current source include feedback loop to improve the output impedance of current source, amplitude control circuit to adjust amplitude of current source and the initial phases which are considered for reducing crest factor (CF) of multisine excitation signals to obtain a further SNR improvement, compared to random phases which are used in previous design. frequencies simultaneously, a FPGA-based multi-frequency current source is designed. In order to improve the output impedance of current source and obtain more impedance information at different. Multi-frequency electrical impedance tomography has been evolving from the frequency-sweep approach to the multi-frequency simultaneous measurement technique which can drastically reduce measuring time and will be increasingly attractive for time-varying biological applications. The current (I S) of resonant differential structure will also be the influence of the inductances including load inductance (L L) and external inductance (L Q2). The sum of load resistance (R L) and series resistance (R S) must be less than negative differential resistance (R N) which the stable phenomena will occur. The external inductance (L Q2) will increase nonlinearly, as the external inductance (L Q2) is increased. When the external inductance (L Q2) is increased, the self-resonant frequency of oscillation will decrease nonlinearly. The resistive cutoff frequency (f r) of oscillation will be not the influence of internal inductance (L Q1). The f SR will be increased, as the internal inductance is decreased. We can understand the spontaneous oscillation frequency (f SR) is inversely proportional internal inductance (L Q1). increased, the output current density of resonant tunneling structure is decreased. As the bias voltage of resonant tunneling structure is. The characteristic of negative differential resistance is constructed by using the relationship of current to voltage curve. In the proposed model, the equivalent circuit of resonant tunneling structure including a nonlinear negative differential resistance element, a series resistance, a junction capacitance, and two inductances is explored. The results will provide valuable references and insights for future design optimizations of temperature susceptible circuits. On the other hand, most of the small-signal parameters show a positive trend with temperature, except for the intrinsic base resistance Rbi, intrinsic base–collector capacitance Cbc, intrinsic base–emitter capacitance Cbe, and common-base current transport factor α0. And the peak current gain declined from 44.04 to 36.09 with the temperature increased from 25 ☌ to 125 ☌. Most of the DC parameters show a negative with temperature, for example the temperature coefficients of the VBE,on and VBC,on are −1.4 and −1.48 mV/☌, respectively. The thermal behavior of DC and equivalent circuit parameters along with their temperature coefficients were analyzed and reported for the first time using the same. Temperature-dependent DC and small-signal analysis have been carried out on 0.7 μm × 15μm InGaAs/InP double heterojunction bipolar transistors over a temperature range of 25 ☌–125 ☌ by on-wafer S-parameter measurements up to 50 GHz.
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