GB1240335A - Improvements in or relating to frequency-selective resistance-reactance networks - Google Patents
Improvements in or relating to frequency-selective resistance-reactance networksInfo
- Publication number
- GB1240335A GB1240335A GB2237968A GB2237968A GB1240335A GB 1240335 A GB1240335 A GB 1240335A GB 2237968 A GB2237968 A GB 2237968A GB 2237968 A GB2237968 A GB 2237968A GB 1240335 A GB1240335 A GB 1240335A
- Authority
- GB
- United Kingdom
- Prior art keywords
- network
- amplifiers
- networks
- switch
- response
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/04—Frequency selective two-port networks
- H03H11/12—Frequency selective two-port networks using amplifiers with feedback
- H03H11/1217—Frequency selective two-port networks using amplifiers with feedback using a plurality of operational amplifiers
Landscapes
- Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
Abstract
1,240,335. Active filters; transistor oscillators and amplifiers. ADVANCE ELECTRONICS Ltd. 9 May, 1969 [10 May, 1968], No. 22379/68. Headings H3T and H3U. A frequency selective network comprises a two section resistance-reactance ladder network C1R1, C2R2, Fig. 3, with the outputs from the two sections 2, 3 fed to a combining circuit 7. Buffer amplifiers 19, 20 may be included between the networks and the combining circuit and a further buffer (21, Fig. 5, not shown) may be included between the two C.R. networks. The resistances and reactances may be interchanged, Fig. 4 (not shown). The network is basically bandpass, but may be modified by the provision of various feedback paths. As shown in Fig. 3, a resistive network 12, 17, 18 and a switch 16 are added. With the switch in position c the basic bandpass response is obtained, in position b an allpass response is obtained, and in position a bandstop is obtained. In order to obtain a high pass or low pass response additional feedback paths are provided from amplifiers 19, 20 via a network 30, Fig. 9, and are combined with the input signal 26 in a further combining stage 28. Positive feedback may be added to improve the Q factor, Fig. 6 (not shown). The network may be used in a phase shift oscillator by connecting the terminal 8 of Fig. 3 back to terminal 1 with the switch in the "allpass " position, Fig. 7 (not shown). The various amplifiers in such an oscillator may be realized by transistor circuits, Fig. 10 (not shown). In all the circuits, the C.R. networks may be replaced by LR ones.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2237968A GB1240335A (en) | 1968-05-10 | 1968-05-10 | Improvements in or relating to frequency-selective resistance-reactance networks |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2237968A GB1240335A (en) | 1968-05-10 | 1968-05-10 | Improvements in or relating to frequency-selective resistance-reactance networks |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1240335A true GB1240335A (en) | 1971-07-21 |
Family
ID=10178432
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2237968A Expired GB1240335A (en) | 1968-05-10 | 1968-05-10 | Improvements in or relating to frequency-selective resistance-reactance networks |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1240335A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2170369A (en) * | 1985-01-29 | 1986-07-30 | Ampex | Voltage controlled equalizer |
US6340913B1 (en) | 1999-08-19 | 2002-01-22 | Fast Analog Solutions Limited | Filter circuit with positive feedback loop |
-
1968
- 1968-05-10 GB GB2237968A patent/GB1240335A/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2170369A (en) * | 1985-01-29 | 1986-07-30 | Ampex | Voltage controlled equalizer |
GB2170369B (en) * | 1985-01-29 | 1989-06-07 | Ampex | Voltage controlled equalizer |
US6340913B1 (en) | 1999-08-19 | 2002-01-22 | Fast Analog Solutions Limited | Filter circuit with positive feedback loop |
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