First-order High-pass Filters Research Articles

Low power analogue equaliser with adaptive digital tuning for fast ethernet

This work presents an analogue equaliser with digital tuning. It compensates the losses introduced by up to 120 m long category 5 unshielded twisted pair cables and baseline wander (BLW). The equaliser is designed for Fast Ethernet with a symbol rate of 125 MHz. A g m -C filter, based on three first-order high pass filters, is used to compensate the cable loss. To minimise power consumption, three operational transconductance amplifiers (OTAs) are merged into a novel multi-input OTA structure. Additionally, a robust digital control logic is presented to automatically adjust the parameters of the equaliser for different cable lengths. A fast settling time below 250 µs is demonstrated for different scenarios. The equaliser is fabricated as part of a Fast Ethernet PHY chip in a 180 nm CMOS technology of GLOBALFOUNDRIES. Measurement results demonstrate error-free data transmission (bit error rate below 10 −12 ) for cable lengths up to 120 m. The power consumption of the analogue equaliser ranges from 2.3 mW (short cable) to 6.5 mW (120 m cable). To the best of the authors’ knowledge, this is the lowest power consumption of an analogue equaliser for Fast Ethernet, supporting additional BLW and flat loss compensation reported to date.

Снижение мощности высокочастотных помех в сигнале управления автоматических систем гребенчатыми фильтрами

The article addresses the matter of reducing the power of high-frequency noise in the control signal produced by industrial automatic systems through the use of algorithms implementing the properties of comb filters in microprocessor controllers. The specific features relating to the frequency responses of open- and closed-loop automatic control systems of industrial facilities are analyzed - both taken alone and in combination with the characteristics of comb filters. The frequency properties of three filter groups that are conventionally used in continuous automatic control systems are compared with three groups of comb filters that implement similar functions. As applied to control tasks, such filters include real differentiating sections or first-order high-pass filters, first-order lag sections or low-pass filters, and proportional sections. The ratios between the parameters of continuous filters and comb filters at which their frequency properties coincide in the operating frequency band are determined. These ratios known, it becomes possible to synthesize the controllers of systems using the existing techniques. It is shown that the amplitude-frequency responses of comb filters have dips in the high-frequency band, due to which the high frequency noise power is finally decreased by up to 30%. The advantage of comb filters in control systems lies in simplicity of implementing them in digital form in a microprocessor controller. The application of comb filters in automatic control systems makes it possible to cut undesirable harmonic noise of large amplitude in the control signal.

Comprehensive comparison based on meta-heuristic algorithms for approximation of the fractional-order Laplacian sα as a weighted sum of first-order high-pass filters

To implement an approximation of the fractional order Laplacian operator sα as a weighted sum of high pass filter sections, it is essential to extract the cutoff frequencies and filter gains of each section in order to achieve the lowest error possible. Therefore, in this work, five meta-heuristic optimization algorithms are tested in this problem based on a weighted sum objective function. The employed algorithms include the: ant-lion optimizer, cuckoo search algorithm, flower pollination algorithm, whale optimizer, and multi-verse algorithm. A comparison is carried out between the results of these algorithms based on the relative percentage error in magnitude and phase of the obtained approximation in order to endorse the most recommended algorithm. The main outcome is that the Cuckoo search and ant-lion optimizers are capable of identifying the required filter parameters with the least phase and magnitude relative error and with a higher convergence rate.

Derivation of low-power first-order low-pass, high-pass and all-pass filters

In this letter, a new voltage-mode (VM) configuration for providing low-power and simultaneous realization of first-order low-pass, high-pass and all-pass filters is presented. The output of the al...

Vibrationless Access Control of a Positioning Mechanism for High-Order Natural Modes of Vibration. 3rd Report, Vibrationless Acceleration Control.

This paper presents vibrationless acceleration control of a vibratory positioning mechanism with robustness to high-order natural modes of vibration. From the veiw point of the continuously stricter requirements for high-precision positioning, it is desirable to eliminate residual vibration of higher-order natural modes of vibration at a target position. To obtain a vibrationless acceleration control force which does not excite higher-order natural modes of vibration, two frequency-shaped cost functionals weighted by first-order and second-order high-pass filters are used in the optimal control theory. The control forces have smaller frequency components in the high-frequency region as compared with the minimum heat generation vibrations acceleration control force when the control time is longer than 0.7 times the natural period of the first natural mode of vibration. The performances of the proposed vibrations acceleration control forces are demonstrated with experimental results using a flexible swing arm positioning mechanism.

Vibrationless Access Control of a Positioning Mechanism for High-Order Natural Modes of Vibration. 2nd Report. Vibrationless Velocity Control.

This paper presents vibrationless velocity control of a vibratory positioning mechanism with robustness for high-order natural modes of vibration. From the requirement for high-precision positioning, it is desirable to eliminate residual vibration of higher-order natural modes of vibration at a target position. To obtain a feedforward access control force which provides a strict final motion state without exciting higher-order natural modes of vibration, two frequency-shaped cost functionals whose weighting functions are represented by first-order and second-order high-pass filters are used in the optimal control theory. The control forces have smaller frequency components in the high-frequency region as compared with the conventional feedforward control forces. The performances of the proposed vibrationless access control methods are demonstrated with experimental results using a flexible swing arm positioning mechanism.