GB682233A - Improvements in or relating to electrical circuits for the production of subjective auditory effects - Google Patents
Improvements in or relating to electrical circuits for the production of subjective auditory effectsInfo
- Publication number
- GB682233A GB682233A GB7819/47A GB781947A GB682233A GB 682233 A GB682233 A GB 682233A GB 7819/47 A GB7819/47 A GB 7819/47A GB 781947 A GB781947 A GB 781947A GB 682233 A GB682233 A GB 682233A
- Authority
- GB
- United Kingdom
- Prior art keywords
- linear
- valve
- amplitude
- amplifier
- circuit
- 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
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/66—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G5/00—Tone control or bandwidth control in amplifiers
- H03G5/16—Automatic control
- H03G5/18—Automatic control in untuned amplifiers
- H03G5/20—Automatic control in untuned amplifiers having discharge tubes
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Amplifiers (AREA)
Abstract
682,233. Transmission systems. STANDARD TELEPHONES & CABLES, Ltd. March 21, 1947 [Oct. 8, 1941], No. 7819/47. Class 40 (iv). In a circuit of the kind described in Specification 649,709 in which a non-linear device is used to distort the frequencies transmitted within a narrow band so as to give the listener the impression of a wideband transmission, the non-linear device is automatically controlled so as to reduce distortion during transients. In the arrangement shown in Fig. 8, the valve T1 is normally biased to act as a linear device. On receipt of a signal through a filter F, a class " C " amplifier T2 applies a positive bias to T1 which then operates on a non-linear basis. A delay circuit R4, R5, C4 defers the change-over from linear to non-linear operation for the initial transient portion of the signal and permits a rapid return to linear operation at the commencement of a decay transient. In another arrangement, Fig. 9, the valve T1 is biased so as to operate on a non-linear basis only for signals above a critical amplitude. A voltage derived from the output of a pentode T3, amplified at T4 and rectified by a double diode T5 is applied to the second control grid of T3 to limit the output of T3 to an amplitude very little greater than the amplitude required to operate T1 on a non-linear basis. In the arrangement shown in Fig. 10, frequencies outside the range to be transmitted are selected by a tuned circuit TC amplified at A and applied to the second control grid of pentode T13. The valve T1 is biased so as to operate as a class " A " amplifier for signals below a critical amplitude. Non-linear distortion is introduced only when the frequencies selected by TC raise the output of T13 above the critical amplitude for T1. In another arrangement, Fig. 11 (not shown), the amplitude of the input to T1 is raised above the critical amplitude only when the output of T13 is raised by regeneration brought about by feedback from the plate of T13 to the second control grid over a tuned phase shifting network. Two distorting valves T11, T12 (Fig. 12) may be arranged in push-pull. The bias of each valve is automatically controlled by a circuit comprising an amplifier T9, a double-diode T10 and a delay circuit R14, R15, C10. Valve T11 is biased by a battery EC4 and normally operates as a linear amplifier. When a signal arrives, T10 operates and builds up a voltage across R15 until, after a delay, the bias on T11 is destroyed and the valve operates on a non-linear bases. In a similar manner, T12 which is normally operated on a non-linear basis changes over to linear operation on the arrival of a signal. The circuits are so adjusted that both valves T11, T12 operate together on a linear basis for a short interval after the onset of the signal. An amplifier PA, a filter FX0 and a loud-speaker LS are used to simulate the narrow band transmission characteristics of the apparatus to be used in practice so that the circuit can be adjusted by experiment to give the most satisfactory results.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US414137A US2315249A (en) | 1941-10-08 | 1941-10-08 | Pseudo-extension of frequency bands |
Publications (1)
Publication Number | Publication Date |
---|---|
GB682233A true GB682233A (en) | 1952-11-05 |
Family
ID=23640105
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB7819/47A Expired GB682233A (en) | 1941-10-08 | 1947-03-21 | Improvements in or relating to electrical circuits for the production of subjective auditory effects |
Country Status (3)
Country | Link |
---|---|
US (1) | US2315249A (en) |
BE (1) | BE470915A (en) |
GB (1) | GB682233A (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3075044A (en) * | 1958-05-05 | 1963-01-22 | Tonalyzer Inc | Method and apparatus for obtaining sound |
US4150253A (en) * | 1976-03-15 | 1979-04-17 | Inter-Technology Exchange Ltd. | Signal distortion circuit and method of use |
US5930373A (en) * | 1997-04-04 | 1999-07-27 | K.S. Waves Ltd. | Method and system for enhancing quality of sound signal |
US6285767B1 (en) | 1998-09-04 | 2001-09-04 | Srs Labs, Inc. | Low-frequency audio enhancement system |
US7031474B1 (en) | 1999-10-04 | 2006-04-18 | Srs Labs, Inc. | Acoustic correction apparatus |
US7277767B2 (en) | 1999-12-10 | 2007-10-02 | Srs Labs, Inc. | System and method for enhanced streaming audio |
US8050434B1 (en) | 2006-12-21 | 2011-11-01 | Srs Labs, Inc. | Multi-channel audio enhancement system |
PL2798737T3 (en) | 2011-12-27 | 2019-05-31 | Dts Inc | Bass enhancement system |
WO2014190140A1 (en) | 2013-05-23 | 2014-11-27 | Alan Kraemer | Headphone audio enhancement system |
-
0
- BE BE470915D patent/BE470915A/xx unknown
-
1941
- 1941-10-08 US US414137A patent/US2315249A/en not_active Expired - Lifetime
-
1947
- 1947-03-21 GB GB7819/47A patent/GB682233A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
US2315249A (en) | 1943-03-30 |
BE470915A (en) |
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