(IJCSIS) International Journal of Computer Science and Information Security, Vol. 11, No. 12, December 2013
A New Current-Mode Multifunction Inverse Filter Using CDBAs Anisur Rehman Nasir
Syed Naseem Ahmad
Dept. of Electronics and Communication Engg. Jamia Millia Islamia, New Delhi-110025, India
Dept. of Electronics and Communication Engg. Jamia Millia Islamia, New Delhi-110025, India
Abstract: Abstract: A novel current-mode multifunction inverse filter configuration using current differencing buffered amplifiers (CDBAs) is presented. The proposed filter employs two CDBAs and passive components. The proposed circuit realizes inverse lowpass, inverse bandpass and inverse highpass filter functions with proper selection of admittances. The feasibility of the proposed multifunction inverse filter has been tested by simulation program. Simulation results agree well with the theoretical results. Keywords : CDBA, CDBA, multifunction, inverse filter
Mode multifunction multifunction inverse filter using using CDBAs. CDBAs. The proposed circuit realizes all the basic filter functions in inverse mode i.e.inverse lowpass (ILP), inverse highpass (IHP) and inverse bandpass (IBP) by proper selection of types of admittances.
1.
2.
CIRCUIT DESCRIPTION
The current differencing buffered amplifier (CDBA) is recently introduced as an active element [10]. The CDBA is suitable for realization of current-mode continuous time filterfunctions because of several advantages like free from parasitic capacitances, differential nature at its input port, high slew rate and wide bandwidth.
INTRODUCTION
The design of inverse filter is useful in Communication and instrumentation engineering. These filters are used to reverse the distortion of signal incurred due to signal processing and transmission.The transmission.The distorted signal is to be converted to the input signal. The inverse filtering is used to inverse the transfer characteristic of the original signal [1, 2].
The circuit symbol of CDBA is shown in Fig.1 and its port relations are given in equation. equation.
,
Several continuous time analog inverse filters are available in literature [2-11].The most of the inverse filter circuits available in literature are voltage–mode circuit. The voltage mode inverse filters are realized generally by CFOAs, CCIIs CCIIs and CDBAs CDBAs [6,7,9,11]. [6,7,9,11]. In current-mode current-mode the inverse filters and allpass filter have been realized using FTFNs [2-5] and CDTA [8] respectively.
, and
(1)
iw
V p
ip
Vw
w
p
Vw
CDBA
Vn
Leuciuc [2] proposed a general method for realizing inverse filter using nullors. B. Chipipop et al [3] and H. Y. Wang et al [4] proposed current-mode universal filters using FTFNs. M.T. Abuelmatti proposed current-mode inverse filter using FTFN [5]. S.S. Gupta Gupta et al [6] and H.Y. Wang et al [7] proposed voltage mode inverse filter configuration using CFOAs that realize inverse lowpass, inverse highpass and inverse bandpass filter from suitable choice of admittances. N.A. Shah et al [8] proposed inverse allpass filters using CDTAs. R. Pandey et al [12] proposed voltage-mode universal inverse filter using CDBAs which realizes all basic inverse filter functions. However to our knowledge, there are no current-mode inverse filter using CDBA. Therefore, in his communication communication an effort is made to realize current-
in
n
z
ip
Vz
Fig.1 Circuit Symbol of CDBA The proposed current-mode multifunction inverse filter circuit is shown in Fig.2. The routine analysis of circuit yields the current transfer functionsas follows
IIO YY YY YY Y Y 2
where
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Vz
(IJCSIS) International Journal of Computer Science and Information Security, Vol. 11, No. 12, December 2013
IIO s CG ⁄ sCC s 1CG C G GG6
Y sC G Y sC G sC G Ns sC G sC 3 If admittances chosen are , then
p
, and
The natural angular frequency and the pole Q-factor of the filter are
7 1 8
z
Iin CDBA1 n
Y1
w
Y5 Y4
The gain constants of ILP, IHP and IBP responses are given by
Y2 w
, ,
p CDBA2
IO z
n
Y6
3.
SENSITIVITY ANALYSIS
12 12 12
Y3
The passive sensitivities of and Q for the proposed current-mode inverse filtercan beexpressed as
Fig.2 Proposed Multifunction Inverse Filter
Y Y Y, andand Y
By proper selection of admittances for , , as shown in Table-I, differentinverse filter functions can be realized. Table I Response ILP IHP IBP
0 0 0
It is observed that the passive sensitivities are lesser than unity in magnitude. Hence the performance of proposed current-mode multifunction inverse filters are not affected.
0 0 0
4. SIMULATION RESULT
The transfer function of the ILP, IHP and IBP can be expressed as
The proposed current-mode multifunction inverse filter has been simulated with simulation software. The multifunction multifunction filter has been designed designed for f O =796.18 KHz and Q=1. The CDBAs have been realized withcommercially available AD844s. The equal values of passive components are used. The supply voltages are ±12V. All the resistors are taken as 10K Ω and capacitors as 20pF. The simulated frequency characteristics for inverse lowpass, inverse bandpass and inverse highpass filter functions are shown in Fig.4. The simulation results agree well with theoretical analysis of the filter.
IIO GG ⁄ sCC s C1G C G GG4 IIO s CC ⁄ sCC s 1CG C G GG5 51
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(IJCSIS) International Journal of Computer Science and Information Security, Vol. 11, No. 12, December 2013
simulation results are in agreement with theoretical analysis. REFERENCES
T 30.00
[1]J. K. .Tugnait, “Identi fication and deconvolution of multichannel linear non-Gaussian processes using higher order statistics and inverse filter criteria,” IEEE Transactions on Signal Processing, vol.45,no.3,p.658–672,1997.
20.00 ) B d ( n i a G
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[2]A.Leuciuc, “Using nullors for realisation of inverse transfer functions and characteristics,” characteristics,” ElectronicsLetters,vol. ElectronicsLetters,vol. 33, no. 11, p. 949951,1997
0.00 10k
100k
1M
10M
Frequency (Hz)
[3]B. Chipipop and W. Surakampontorn, “Realisation of current-mode FTFN-based inverse filter,” Electronics Electronics Letters, vol. 35, no. 9, , p. 690-692. 1999
(a) Inverse Lowpass Filter
[4] H. Y. Wang and C. T. Lee, “Using nullors for realisation of currentmode FTFN-based inverse filters,” Electronics Letters, vol. 35, no. 22, , p. 1889-1890. 1999
T 40.00
30.00
[5] M. T. Abuelma’atti, “Identification of cascadable current-mode filters and inverse filters using single FTFN,” Frequenz, Vol. 54, No. 11, , p. 284-289. 2000 2000
) B d ( n 20.00 i a G
[6] S. S. Gupta, D. R. Bhaskar and R. Senani, “New analogue inverse filters realised with current-feedback op- amp ”, International Journal of Electronics, vol. 98, no. 8, p. 1103–1113, 2011
10.00
0.00 10k
100k
1M
10M
[7]H.Y. Wang, S.H.Chang, T. Y. Yang, and P.Y. Tsai, “A Novel multifunction multifunction CFOA-based inverse filter”, Circuits and Systems, 2, 14-17 , 2011,
Frequency (Hz)
(b) Inverse Bandpass Filter
[8]N. A. Shah, M. Quadri, and S. Z. Iqbal,“High output impedance current-mode allpass inverse filter using CDTA,” Indian Journal of Pure and Applied Physics,vol.46,no.12,p.893–896,2008. Physics,vol.46,no.12,p.893–896,2008. T 80.00
[9]N. A. Shah and M. F. Rather, “Realization of voltage-mode CCII based allpass filter and its inverse inversion”, India J. of Pure and Applied Physics, 44, 3, 269-271, 2006
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[10]C. Acar and S. Ozoguz, “A new versatile building block: current di erencing erencing bu ered ered ampli fier suitable for analog signal processing filters,” Microelectronics Journal,vol.30,no.2,p.157–160, 1999.
ff
20.00
ff
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[11]R. Pandey, N. Pandey,T. Negi and V.Garg, “CDBA based universal inverse filter”, ISRN ElectronicsVolume2013, 2013
-20.00 10k
100k
1M
10M
Frequency (Hz)
(c) Inverse Highpass Filter
Fig.4 Frequency Response of InverseFilters 5. CONCLUSION
A new current-mode multifunction inverse filter using CDBAs has been presented. The proposed circuit uses two CDBAs and passive elements. The inverse lowpass, inverse bandpass and inverse highpass filter functions are realized by proper selection of passive elements. The
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