Implementation of a Sixth Order Active Band-pass R-Filter. Igwue,G.A,Amah,A.N,Atsuwe,B.A

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1 Internatinal Jurnal f Scientific & Engineering Research, lume 5, Issue, April-0 ISSN Implementatin f a Sixth Order Active Band-pass R-Filter 598 Igwue,G.A,Amah,A.N,Atsuwe,B.A Abstract In this paper, an active band-pass R- filter utput respnse at different values f center frequency using MAPLE prgramming is carried ut. A sixth rder active band pass R-filter are cnstructed at center frequencies f 0 khz and 00 khz and quality factrs f, 5,, 8 and 0 and rll ff rate f 0dB/decade. The architecture used is the multiple feedbacks. The filter parameters and values fr the passive cmpnents were calculated, the gain and phase respnse were then simulated with MAPLE prgramming. The simulatin shws that at high Quality factrs, the bandwidth f the filter respnse reduces cnsiderably while its frequency selectivity increases withut a shift in its center frequency. This is an indicatin that the filter will functin well at high frequencies and perfrm prly at lwer frequencies. This result als shws that the R-filter is mst selective at a quality factr f Q=8 and centre frequency f f = 00KHz Index Terms R-filter, Quality factr, Band pass, MAPLE. INTRODUCTION A Filters are usually classified accrding t filtering range, frequency respnse in pass band, and circuit cmpnent. Classified by filtering range, there are fur types f filters: lw-pass, high-pass, band-pass, and band-reject filters. Accrding t frequency respnse in pass band, there are tw types: Butterwrth and Chebyshev filters. Accrding t circuit cmpnent, they are active and passive filters. Passive filters are circuits that cntain nly passive cmpnents (resistrs, inductrs and capacitrs) cnnected in such a way that they will pass certain frequencies while rejecting thers. Active filters, which are the nly type cvered filter is defined as a netwrk which passes a certain prtin f a frequency spectrum and blcks the remaining prtin f the spectrumthe term blcking means that the magnitude respnse H ( j ) f the filter is apprximately zer fr that frequency range. In ther wrds, a filter is a frequency selective device r system[]. The active filter withut the capacitr is called an active-r filter; and has received much attentin due t its ptential advantages in terms f miniaturizatin, ease f design and high frequency perfrmance [5],[]. It has been als pinted ut in the literature that active-r netwrks ffer substantially lw sensitivity characteristics as cmpared t R-C active structures in this paper, emply active []. Althugh several papers have been published n evaluatin f the secnd rder active-r filter, we have nt cme acrss any reprted circuit regarding direct cupled circuit fr realizing third-rder active-r filters with feedfrward input signals. This gives greater stp-band attenuatin and sharper cut-ff at the edge f the passband. The band-pass respnse is characterised by a frequency band between the lwer cut ff frequency, f L and upper cut ff frequency, f H such that input signals with frequencies(f) within the band f L(i-e f L<f<f H) less than f and f itself is less than f H (f L< f<f H ) emerge unchanged while thse signals with frequencies utside the band are attenuated. The difference (f H - f L) is called the bandwidth f the filter, and the pint f frequency spectrum at which the band is centered is called the centre frequency f [9]. Citatins METHODOLOGY Igwue,G.A is a prfessr f Electrical/Electrnics Engineering in the Department f Electrical/Electrnics,federal university f Agriculture,Makurdi,Benue State. Amah,A.N is a senir lecturer with Ph.D in Slide State physics in the Department f physics Federal University f Agriculture,Makurdi.. E- mail:dunzalex@yah.cm Atsuwe,B.A is currently pursuing Ph.D degree in Engineering physics in the dpartment f physics.he is a lecturerii in the deprtment f science eductin Fedrl university f agriculture,makurdi.. ellamneuter@yah.cm cmpnents (transistrs r peratinal amplifiers) plus resistrs, inductrs and capacitrs. Active filters are widely used in mdern cmmunicatin systems, because they have the fllwing advantages[]:. Because the transfer functin with inductive characteristic can be achieved by particular circuit design, resistrs can be used instead f inductrs.. The high input impedance and lw utput impedance f the peratinal amplifier means that the filter circuit is excellent in islatin characteristic and suitable fr cascade.. Because active cmpnents prvide amplificatin, therefre active filters have gain. The circuit cnfiguratin fr the sixth rder active R- Band pass filter was gtten frm the wrk f [8] which is n the secnd rder active Band pass filter as shwn in Fig. The resistr values were calculated using equatin and. 0

2 Internatinal Jurnal f Scientific & Engineering Research lume 5, Issue, April-0 ISSN A K Gain ( st ) The vltage transfer functin T f = i f the circuit is given CC st A k K R R s T stk i A A k k R by[8] as; () R Where K is the attenuatr given by equatins and abve. Thus the rle f attenuatr K is that it cntrls the pen lp R gain f peratinal amplifiers used in the circuit. Thus R adjustment f K results in cntrl f centre frequency f the band pass filter. The resistances R s can be varied using Field Effect Transistr (FET) replaced resistances, thus giving single cntrl f tw attenuatrs K. The quality factr Q is Fig : Circuit diagram f a secnd rder active R-band pass filter independently adjusted using element K, which is adjustable thrugh resistance R. The sixth rder active R-band pass filter is btained by cascading f the secnd rder active R-band pass filter f Fig. and is represented in Fig.. Since filter rders determine the gain and selectivity f the filter, there The architecture that has been used t implement bth the sixth rder active R-band-pass have been attempts t imprve n the filter rders hence the filter is the multiple feed-back need t cascade filters. Fig shws the simplest frm f a filter tplgy which can be realized thrugh cascading f the which is called the Secnd rder. If a better functinality f the secnd rder filter stages. The circuit diagram in Fig. shws filter in terms f selectivity is needed, then there will be the the implemented circuit cmpsed f triply cascaded secnd need t put tw f the secnd rders tgether t make the rder active R-band pass filter. furth rder. Again if a much higher gain is needed, then we increase the rder. Cnsequently the higher the filter rder, the Analysis higher the gain and the filter selectivity.[].furthermre, there has been n knwn literature fr the sixth rder Band k R pass filter, s it was selected. The circuit perfrmance was ( k ) studied with different values f quality factr (Q =, 5,, 8 R = () and 0) with cnstant f=0 khz. A T (5) k R k ) ( R = () Since k and k are attenuatrs, their values are given as 5 U 5 U k = k = Q f A T A T () (). 0 which is the gain The value f is taken as bandwidth prduct f the amplifier. The gain f the filter can be determined accrding t[8] as; 0 rms 0 Hz 0 R - R5 R 5 R - U R8 R - R R 5 R5 U5 5 R - U8 R R - R R R9 5 th -rder Active Bandpass filter multiple FeedBack Fig : Circuit Diagram f Sixth Order Active-R Band Pass Filter RESULT Fr a centre frequency f =0kHz, the value f R was chsen t R - U R8 R0 0

3 Internatinal Jurnal f Scientific & Engineering Research lume 5, Issue, April-0 ISSN be 00k. After the substitutin in the same equatin,r was calculated t be.0k.the results fr the maximum pass band gain and the bandwidth fr the filter at f=0khz and f=00khz are presented in Tables and respectively,while their respective magnitude respnses are shwn in Figures and. Table. Maximum PassBand Gain and Bandwidth f the Sixth-Order Active R- BandPass Filter at f 0 = 0kHz As demnstrated in this dcument, the numbering fr sectins upper case Arabic numerals, then upper case Arabic numerals, separated by perids. Initial paragraphs after the sectin title are nt indented. Only the initial, intrductry paragraph has a drp cap. Table. Maximum PassBand Gain and Bandwidth f the Sixth-Order Active R- BandPass Filter at f 0 = 00kHz Qualit Maximu -db Lwer Upper Bandwid Quality Maximu -db Lwer Upper y m Pass- alu -db -db h factr m alue(db -db -db factr Band e alue alue (Hz) (Q) Passban ) alue alue(h (Q) gain(db) (db) (Hz) (Hz) d (Hz) z) ,9. gain(db) Bandwid th (Hz) 0,

4 Internatinal Jurnal f Scientific & Engineering Research lume 5, Issue, April-0 ISSN Fig.: Sixth rder active R-band pass filter at centre frequency f = 0 khz and Q=, 5,, 8, 0 respectively. Fig. : Sixth rder active R- band pass filter at centre frequency f = 00 khz and Q=, 5,, 8, 0 respectively 0

5 Internatinal Jurnal f Scientific & Engineering Research lume 5, Issue, April-0 ISSN DISCUSSION Table presents results fr f 0= 0kHz, the pass band gain increases frm a value f.db at Q= t 9.00 db at Q=0. 0 amplifiers were used. This filter can als be used as a narrw band device because the selectivity is high, as well as t btain high gains. The bandwidth decreases frm a value f 9.Hz t 9.Hz at Q=8 and Q=0. This implies gd behavir f the filter at this centre frequency. Als the filter wrks and it has high selectivity which is in line with literature. Thery specifies that increase in Q, leads t increase in the gain (G) and increase in Q yields a decrease in the bandwidth. Als the increase in f gives a decrease in the bandwidth. Furthermre, at a cnstant f =00kHz, as presented in table ACKNOWLEDGMENT The authrs wish t thank mr Ahemen I,Kureve,D.T and Ry,A fr their immense cntributins t the success f this wrk. REFERENCES []Carter, B(00): Filter Design in thirty secnds. Texas Instrument Inc. Dallas.USA. [] Hashemi, K (00): Filter design guide. [] http/ Amplifier Basics (0//008). []Huelsman, L. P(9): Equal alued Capacitr Active-RC Netwrk Realizatin f third Order Lwpass Butterwrth Characteristic.,the pass band Gain is.db at Q= and increases t.8db Electrn Lett.: 9 9. at Q=0, while the Bandwidth decreases frm 0,0.05 Hz at [5]Hyng, K.K. and RA, J.B(9): An Active Biguadratic Building Blck Q= t 5,88. Hz at Q=0. This implies cnsistent behavir withut External capacitrs, IEEE Transactins n circuit and f the filter at this centre frequency. Als the filter really wrks system, l. CAS-,N. and it has high selectivity which is in line with literature. In []Igwue, G. A(00): Basic circuit thery and Industrial Electrnics fr summary, the active R-band pass filter is characterized by Physicists. Abki Publishers, Makurdi. Nigeria. high gain and narrw bandwidth at bth f = 0kHz and 00kHz. CONCLUSION It can be cncluded frm the abve results that even thugh the cnstructed filter des nt have same values as the simulated results, it still maintains the filter behaviur r characteristics. Therefre the filter perfrms well at f 0= 0kHz and f 0= 00kHz up t a quality factr f Q=8. It is believed that there can be further imprvement in the characteristics if mre precise values f resistrs and better peratinal []Mesami, H(99): Active R Realisatin f Current Mde Highpass Filter.Int.J.Electrnices,: p [8]Prabhat, U. and Pal, K(00): An Active Bandpass realizatin usingamplifier, Old city publishing inc.vl., p. -5 [9]Sergi, F(998): Design with Operatinal Amplifiers and Analg Integrated Circuit, McGraw-Hill. New Yrk, USA. [0]Shinde, G. N; Kadam, A. B; Kurumbatte, S. B and Patil, P.B(00): Study f Active R Secnd Order filter using feedback at Nninverting terminal. Bulletin f pure and applied sciences 0

6 Internatinal Jurnal f Scientific & Engineering Research lume 5, Issue, April-0 ISSN vl.d (), p. -. []Shinde, G. N; Patil, P. B and Mirkute, P.R (00): A third rder active R filter with feed frward input signal. Sadhana vl.8 () []Stark, P. A (00): Band pass filters and Resnance. []Sderstand, M. A(9): Design f Active R Filter using nlyresistance and Operatinal Amplifier.Int.J.Electrnics, l.(n0:8): p. -. []Sderstand, M. A and Mitra, S.K(9): Sensitivity Analysis f Third Order Filter Int.J.Electrn.0; p [5]Srinivasan, S(99): Synthesis f transfer functin using the peratin amplifier ple. Int. J. Electrn.; p []Wayne, S(0): Active Band pass Filter, Electrnics-Tutrials.ws. P.-8 0