A third-order active-R filter with feedforward input signal

Abstract

A realization of voltage-mode transfer functions with feedforward input signal for third-order active-R filter using an oprational amplifier has been presented. This filter is useful for high frequency operation, monolithic IC implementation and is easy to design. The single circuit gives three filter functions, low pass, high pass and band pass. This filter circuit can be used for different Q and f 0 with high passband gain. This gives better stop band attenuation and sharper cutoff at the edge of the passband.

A Comparison of Higher-Order Active Band-Pass R-Filter Response with Equivalent Band-Pass RC-Filter Response at Varying Q-Factors

“…This observation is contrary to report by Shinde et al [8] that each section is a two pole network. The total roll-off ( ) T L ∆ of the R-filter network in Figure 2 is close to the ideal value of 60 dB/decade ≈ for a third-order configuration (Figure 3 and Figure 4, Table 3).…”

“…The building block of the R-filter is the internally compensated operational amplifiers (Op-Amps) [4] [5]. In addition to frequency stabilization by the R-filter network, it also has the potential advantages of miniaturization, ease of design and high frequency performance [6]- [8]. Active R-filters have been reported to be suitable for medium-Q high frequency applications [9].…”

Single-input Multiple-output Signals Third-order Active-R Filter for different Circuit Merit Factor (Q)

“…The Gain roll-off in stop-band varies between 17.6 to 18dB/octave which is close to the ideal value of 18 dB /octave for third order active-R filter .Also, the gain gets stabilized almost at 0 dB for all values of Q ≥ 0.8.Also, the response shows overshoot for all the values of Q ≥ 6. But in previous reported configuration the gain stabilized for Q ≥ 5.Also, overshoot is observed for all the values of Q [8][9][10][11][12][13][14][15]. The analysis for the responses are summarizes in the table 3.…”

A novel DDCC+ based first-order current-mode active-C all-pass filter using a grounded capacitor

“…Substituting the mapped state variable and input signal into Eq. (14) and Eq. (15), and after routine mathematical operations, circuit equations can be derived as given by Eq.…”

“…CMOS integrated structures are mostly preferred in analog designs [13]. The types of passive components used in the integrated circuit topology design determine the category of architecture, such as active-R [14], active-C [11,[15][16][17][18][19][20][21], active-RC [11], or active-only [22] circuits. Passive resistors, which have some disadvantages such as needing a large chip area and a nonaccurate current-voltage proportion, are not employed in the proposed circuit.…”