A CMOS Programmable Fourth-Order Butterworth Active-RC Low-Pass Filter

Zhang, Changchun; Shang, Long; Wang, Yongkai; Tang, Lu

doi:10.3390/electronics9020204

Cited by 15 publications

(9 citation statements)

References 23 publications

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“…As shown in the figure, the complex BPF comprises two biquads in the I and Q paths that are cross-connected by two cross-coupling resistors R xa and R xb . The biquad is based on a two-integrator-loop Tow-Thomas structure, which is widely adopted for baseband LPF designs [14,15]. The biquad in Figure 2 is known as an inverted Tow-Thomas structure since its lossless integrator part is placed before the lossy integrator part [16].…”

Section: Circuit Designmentioning

confidence: 99%

Low-Power CMOS Complex Bandpass Filter with Passband Flatness Tunability

et al. 2020

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We present a low-power CMOS active-resistance-capacitance (active-RC) complex bandpass filter (BPF) with tunable gain, bandwidth, center frequency, quality factor, and passband flatness for Bluetooth applications. A transfer function analysis for a cross-coupled Tow-Thomas biquad structure is presented to prove that the flatness profile of the passband gain can be effectively controlled by independently tuning two cross-coupling resistors. The proposed biquad-based complex BPF was employed to realize a fourth-order baseband analog processor for a low intermediate frequency (low-IF) RF receiver. The baseband analog processor was composed of two complex biquad filters and three first-order variable-gain amplifiers. It was fabricated in a 65-nm RF CMOS and achieved wide tuning capabilities, such as a gain of −15.6 to 50.6 dB, a bandwidth of 1.4–3.9 MHz, a center frequency of 1.5–4.1 MHz, and a passband flatness of −1 to 1 dB. It also achieved an image rejection ratio of 40.3–53.3 dB across the entire gain tuning range. It consumed 1.4 mA from a 1 V supply and occupied an area of 0.19 mm2 on the silicon substrate. The implementation results prove that the proposed complex BPF was able to effectively enhance the signal processing performances through the flexible and wide-range tunability of the passband flatness, as well as that of the gain, bandwidth, center frequency, and quality factor.

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Section: Circuit Designmentioning

confidence: 99%

Low-Power CMOS Complex Bandpass Filter with Passband Flatness Tunability

et al. 2020

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“…Electron guns for non-relativistic magnetrons are mostly based on space charge limitation, and relativistic pulse magnetron electron guns are mostly based on temperature limitation 174 . Electron guns for O-type slow-wave electric vacuum devices such as klystron are mostly based on space charge limitation 175 .…”

Section: Gyrotronmentioning

confidence: 99%

Review of the high-power vacuum tube microwave sources based on Cherenkov radiation

Xu¹,

Xu²,

Liu³

2020

Preprint

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Since the first vacuum tube (X-ray tube) was invented by Wilhelm Röntgen in Germany, after more than one hundred years of development, the average power density of the vacuum tube microwave source has reached the order of 108 [MW][GHz]2. In the high-power microwave field, the vacuum devices are still the mainstream microwave sources for applications such as scientific instruments, communications, radars, magnetic confinement fusion heating, microwave weapons, etc. The principles of microwave generation by vacuum tube microwave sources include Cherenkov or Smith-Purcell radiation, transition radiation, and Bremsstrahlung. In this paper, the vacuum tube microwave sources based on Cherenkov radiation were reviewed. Among them, the multi-wave Cherenkov generators can produce 15 GW output power in X-band. Cherenkov radiation vacuum tubes that can achieve continuous-wave operation include Traveling Wave Tubes and Magnetrons, with output power up to 1MW. Cherenkov radiation vacuum tubes that can generate frequencies of the order of 100 GHz and above include Traveling Wave Tubes, Backward Wave Oscillators, Magnetrons, Surface Wave Oscillators, Orotrons, etc.

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“…Several VM biquads based on active components have been presented in [1][2][3][4][5][6][7]. The applications and advantages in the realization of the VM biquad filters employing the current-feedback amplifier (CFA) as the active building block have also received considerable attention [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

High-Input Impedance Voltage-Mode Multifunction Filter

Wang

Chen

et al. 2021

Applied Sciences

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This paper proposes a high-input impedance voltage-mode (VM) multifunction biquad filter which employs three current-feedback amplifiers (CFAs), three resistors, and two grounded capacitors. The proposed VM multifunction biquad filter has single-input and triple-output and can realize non-inverting low-pass (NLP), inverting band-pass (IBP), and non-inverting band-stop (NBS) voltage responses at the same time without increasing component selection. The proposed VM multifunction biquad filter enjoys the orthogonal tunability of angular frequency and quality factor and also provides the advantage of using only two grounded capacitors, high-input impedance and low active/passive sensitivity. The performance of the proposed VM multifunction biquad filter is verified through its hardware implementation and OrCAD PSpice simulation based on AD844-type CFAs. The circuit analysis, sensitivity analysis, and NLP, IBP, and NBS voltage responses are also shown in this paper. The paper presents a method to effectively reduce the active and passive components, maintain good circuit performance, and reduce circuit costs.

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A CMOS Programmable Fourth-Order Butterworth Active-RC Low-Pass Filter

Cited by 15 publications

References 23 publications

Low-Power CMOS Complex Bandpass Filter with Passband Flatness Tunability

Low-Power CMOS Complex Bandpass Filter with Passband Flatness Tunability

Review of the high-power vacuum tube microwave sources based on Cherenkov radiation

High-Input Impedance Voltage-Mode Multifunction Filter

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