Voltage-mode highpass,bandpass and lowpass filters using two DDCCs

A new configuration for realizing voltage-mode highpass, bandpass and lowpass filters, simultaneously, using two differential difference current conveyors (DDCCs), two grounded capacitors and two grounded resistors is presented. The proposed circuit offers the following features: realization of highpass, bandpass and lowpass signals from the same configuration, no requirements for component matching conditions, the use of only grounded capacitors and resistors, high input impedance, low active and passive sensitivities and simpler configuration due to the use of only two DDCCs and four passive components.     

Current-mode highpass, bandpass and lowpass filters using the operational amplifier pole

The use of the Operational Amplifier (OA) pole has received much attention for its potential advantages of miniaturization, ease of design and high frequency performance. This paper proposes a novel circuit configuration for realizing current-mode filters using the OA pole. The circuit realizes simultaneously highpass, bandpass and lowpass transfer functions. Since the circuit uses the OA pole, it is suitable for high frequency operation.     

Current-mode lowpass, bandpass and highpass biquads using two CCIIs

Two current-mode second-order filter configurations which employ two second-generation current conveyors (CCIIs) and can realise lowpass and bandpass filter responses for one and highpass and bandpass filter responses for the other are presented. The proposed networks offer the following advantageous features: orthogonal control of omega /sub 0/ and Q, use of only two grounded capacitors which make the networks ideal for integration, no requirement for critical matching condition/cancellation constraints, and low passive sensitivities.<>     

Quadrature-modulation-type lowpass and highpass filters

Quadrature-modulation filters, introduced by the author four years ago, can be realised in two different configurations. It is shown that, in the transition bands of the `star?-structured filters, `unwanted? output frequency components (i.e. components not present at the input) are generated, but that, in `lattice-structured? filters, semiequivalent to the corresponding star configuration, such unwanted components are (or can be) suppressed.     

Insensitive current-mode universal filter using dual output current conveyors

A new current-mode universal filter with single input and three outputs employing only three dual output current conveyors and five grounded passive elements is presented. The proposed filter realizes three filter functions simultaneously, all at high impedance outputs. No component matching is required and all the passive and active sensitivities are low. Furthermore, the filter can also realize the notch and all-pass responses. Orthogonal control of the natural angular frequency and the quality factor is achieved.     

Insensitive current-mode bandpass filter implemented from two current conveyors

Two configurations for second order bandpass filters with current transfers are introduced. The circuits, which exhibit reduced values for the active and passive insensitivities, only use four passive components and necessitate two current conveyors. SPICE simulated results, which confirm the theoretical analysis, are given and discussed for current conveyors implemented in a translinear form.<>     

High input impedance voltage-mode lowpass, bandpass and highpassfilter using current-feedback amplifiers

A new configuration for realising high input impedance lowpass, bandpass and highpass filters simultaneously by using three current-feedback amplifiers, three grounded capacitors, three grounded resistors and one floating resistor is presented. The proposed circuit offers the following features: realisation of lowpass, bandpass and highpass signals from the same configuration, no requirements for component matching conditions, orthogonal control of ω₀ and Q, the use of grounded capacitors, low active and passive sensitivities and low output impedance     

Novel realization of monotonic Butterworth-type lowpass, highpass,and bandpass optical filters using phase-modulated fiber-opticinterferometers and ring resonators

A novel realization of monotonic Butterworth-type lowpass, highpass, and bandpass optical filters (from their electrical digital filter characteristics) by cascading the all-pole and all-zero resonators is presented. A graphical method for fast derivation of the transfer functions, quick inspection of the resonance effects, and important characteristics of any photonic circuits is described. It is shown that incorporation of the optical amplifiers and optical phase modulators into the delay lines of two basic optical resonators, whose pole and zero can be adjusted independently of each other, provides great design flexibility which would otherwise not possible using conventional passive optical resonators. Possible applications of these optical filters as optical pulse equalizers and receiver shaping filters in long-haul coherent lightwave transmission systems are discussed. Possible application of basic resonators comprising of optical phase modulators as tunable optical filters for spectrum analyzers is also considered     

High output impedance current-mode universal filter employing dual-output current-controlled conveyors and grounded capacitors

A novel current-controlled two-input three-output current-mode universal filter, which employs only three dual-output controlled-controlled current conveyors (DOCCCIIs) and two grounded capacitors, is presented in this paper. The proposed configuration provides inverting-type lowpass, noninverting-type lowpass, inverting-type bandpass, noninverting-type bandpass, highpass, bandstop and allpass current responses at a high impedance terminal, which enable easy cascadability. The filter also offers an independent electronic control of the natural frequency ω_o and the parameter ω_o/Q through adjusting the bias current of the DOCCCII. No critical matching condition is required for realizing all the filter responses, and all the incremental parameter sensitivities are low. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.     

High output impedance current-mode universal biquadratic filters with five inputs using multi-output CCIIs

Three current-mode universal biquadratic filters each with five input terminals and one output terminal are presented. The first proposed circuit uses three multi-output second-generation current conveyors, two grounded capacitors and three resistors. This circuit offers the following advantageous features: orthogonal controllability of resonance angular frequency and quality factor, high output impedance, the versatility to synthesize all standard filter types without component matching condition and using grounded capacitors. The second proposed circuit uses three multi-output second-generation current conveyors, two grounded capacitors and two resistors. This circuit offers the following advantageous features: using minimum passive components, high output impedance, the versatility to synthesize all standard filter types without component matching condition and using grounded capacitors. The third proposed circuit uses three multi-output second-generation current conveyors, two grounded capacitors and three grounded resistors. This circuit offers the following advantageous features: the versatility to synthesize all standard filter types, high output impedance and using only grounded passive components. Each of the proposed circuits can get five kinds of filter functions by using only one current input signal.     

Signal limitations of the current-mode filters employing current conveyors

It is well known that second-generation current conveyors (CCII) are widely used for the realization of second-order current-mode universal filters. A filter with high-quality factor (Q) and gain constant (K) suffers from various signal swing restrictions especially at its angular resonance frequency (ω₀). This is due to the terminal voltages of the CCIIs limited by the power supply voltages and maximum allowable terminal currents of the CCIIs. In this paper, signal limitations of the CCII-based current-mode filters are investigated in detail. A filter example is given to exhibit the signal limitations of a universal current-mode filter. The time-domain and frequency-domain results of the proposed filter are also given to verify the theoretical analysis.     

High impedance voltage- and current-mode multifunction filters

This paper presents a voltage- and current-mode multifunction filters based on and employing two four-terminal floating nullors (FTFNs) and a single operation transconductance amplifier (OTA). The high-input impedance voltage-mode configuration can simultaneously realize lowpass (LP), bandpass (BP) and notch filtering functions from the same configuration. The circuit employs two grounded capacitors which suits contemporary IC design techniques. The resonance frequency ω₀ and bandwidth ω₀/Q can be independently tuned while as resonance frequency ω₀ and quality factor Q are orthogonally controllable. The current-mode configuration can simultaneously realize LP and highpass (HP) from which notch filtering signal can also be obtained. The input impedance of the circuit is very low while the output currents are available at very high impedances. The resonance frequency ω₀ and bandwidth ω₀/Q can be orthogonally tuned. The high impedance of both the topologies in the two modes facilitates easy cascading for higher-order filter construction. Passive sensitivity figures are low. PSPICE simulation results are also included.     

Low-power CMOS switched-capacitor lowpass filter using current conveyors

A new approach is proposed to the design of high-order switched-capacitor LPFs of megahertz cutoff frequency for communications channel selection. It essentially uses current conveyors instead of op amps to achieve low power consumption. A fifth-order Chebyshev LPF with a 1-MHz cutoff frequency is thus synthesized and fabricated in a 0.35-μm CMOS technology. The LPF consumes less than 10 mW from a 3-V power supply and exhibits a third harmonic distortion better than ?54 dB in response to a 1-V sinusoidal input at the cutoff frequency. The rms noise voltage is at most 1.9 mV in a 2-MHz bandwidth.     

Current-mode lowpass and bandpass filters using the operational amplifier pole

This paper proposes a circuit configuration for realizing current-mode lowpass and bandpass filters using the operational amplifier (op.-amp.) pole. The circuit simultaneously realizes lowpass and bandpass transfer functions using an op.-amp., three resistors and a capacitor. The effects of the paras tic poles (i.e. second and third poles) of the op.-amp. on the gain of a lowpass filter are also presented. Since the circuit uses the op.-amp. pole, it is suitable for high frequency operation.     

高输出阻抗多功能电流模式双二阶滤波器

提出了一种基于多输出端差动差分电流传送器的多功能电流模式滤波器电路结构。该电路用三个多输出端差动差分电流传送器，五个或四个接地电阻和两个接地电容，同时实现了反相和，或同相带通和低通或带通和高通滤波响应特性。分析并模拟了所提出的滤波器的传递特性，PSPICE仿真结果表明，所提出的电路方案正确有效。电路具有灵敏度低，输出阻抗高，滤波器固有频率ωo和品质因数Q相互独立可调，多功能的优点，适于实现全集成连续时间滤波器。     

Brief communication Current-mode highpass and bandpass filters using the operational amplifier pole

A circuit configuration for realizing current-mode highpass and bandpass filters using the operational amplifier (op.-amp.) pole is proposed. The circuit simultaneously realizes highpass and bandpass transfer functions using an op.-amp., two resistors and a capacitor. The effects of parastic poles (i.e. second and third poles) of the op.-amp. are also presented. Since the circuit uses an op.-amp. pole, it is suitable for high frequency operation.     

Insensitive high-output impedance minimum configuration SITO-type current-mode biquad using dual-output current conveyors and grounded passive components

This paper presents a high-output impedance current mode single-input and three-outputs (SITO)-type multifunction filter which employs three dual-output current conveyors to simultaneously realize low-pass, high-pass and band-pass responses. The proposed circuit uses grounded-virtually grounded passive components (which makes the circuit ideal for integration and tuning). Moreover, it has low active and passive component sensitivities and does not require critical matching conditions and cancellation constraints.     

Efficient implementation of tunable ladder filters using multi-output current controlled conveyors

A methodology to realize continuous-time current-mode tunable ladder filters of any order has been presented. This proposed technique individually simulates signal flow graph (SFG) of each branch element from passive filter prototype using only multi-output second generation current controlled conveyors (MCCCIIs) and grounded capacitors. This leads to simple structure, ease of design and suitability for IC fabrication. A third-order Butterworth low-pass filter, a third-order elliptic low-pass filter and a sixth-order Chebyshev band-pass filter are employed to demonstrate the proposed realization scheme. These simulated filters retain minimum requirement of passive and active elements and provide the filter corner frequency tunability. Moreover, the method allows an implementation of the elliptic filters by simply adding floating capacitors to all-pole filter structures.     

Compact bandpass filters using stepped impedance resonators

This paper presents a theoretical analysis of, and experimental results given by, stepped impedance (SI) resonators constructed and used as high-Q resonators in the UHF band. These results made it clear that the Q-factor is higher than conventional capacitor-loaded resonators. Three types of bandpass filters were designed and fabricated using the SI resonators. The filters mentioned in this paper show that excellent performance has been obtained.