One approach to design self-tuning gm-C biquad band-pass filter is considered in this paper. The phase control loop is introduced to force filter central frequency to be equal to input signal frequency what is achieved by adjusting the amplifier transconductance gm. Thanks to that, the filter is robust to parameter perturbations and it can be used as a selective amplifier. In the full tuning range, it has a constant maximum gain at central frequency as well as a constant bandwidth. The 0.25 μm SiGe BiCMOS technology was used during design and verification of the band-pass filter. The filter has 26 dB gain, quality factor Q = 20 and central frequency up to 150 MHz. Simulation results indicate that the total in-band noise is 59 μV rms , the output third intercept point OIP3 = 4.36 dB and the dynamic range is 35 dB. Maximal power consumption at 3 V power supply is 1.115 mW.
The use of analog CMOS circuits at high frequency has gained much attention in the last several years. At the heart of rapid prototyping of these circuits is the concept of using a versatile library of common RF function blocks. The blocks (cells) must be designed to be flexible in terms of drive requirements and loading. This paper presents the results of on-going research in development of phase-synchronizer as common RF function block, used in frequency and phase modulation, frequency synthesis, clock generation recovery, filtering, etc. The proposed circuit is based on series of voltage-controlled all-pass filter as delay chain, and enables phase regulation of analog input signals in wide range. Other characteristics of the input signal, such as amplitude and waveform are not deteriorated. The gm-C voltage-controlled all-pass filter is crucial block of the proposal. The IHP 0.25 um SiGe BiCMOS technology was used for design and verification of the circuit. Simulation results indicate that it is possible to obtain phase regulation in the wide frequency range, from 100 kHz up to 200 MHz
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.