GB931422A - Improvements relating to stereophonic sound transmission systems - Google Patents
Improvements relating to stereophonic sound transmission systemsInfo
- Publication number
- GB931422A GB931422A GB3252258A GB3252258A GB931422A GB 931422 A GB931422 A GB 931422A GB 3252258 A GB3252258 A GB 3252258A GB 3252258 A GB3252258 A GB 3252258A GB 931422 A GB931422 A GB 931422A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signals
- produce
- sidebands
- directional
- stereophonic
- 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
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/86—Arrangements characterised by the broadcast information itself
- H04H20/88—Stereophonic broadcast systems
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Stereophonic System (AREA)
Abstract
931,422. Stereophonic systems. ELECTRIC & MUSICAL INDUSTRIES Ltd. Oct. 12, 1959 [Oct. 11, 1958; Nov. 8, 1958], Nos. 32522/58 and 35920/58. Class 40 (4). [Also in Group XL (c)] In a stereophonic system two directional signals VL and VR derived from sound are linearly combined to form two signals A and B each of which is compatible (viz. such that A and B are never zero for any non-negative values of VL and VR, excluding the case where VL and VR are both zero), from which signals the directional signals VL and VR may be regenerated. As described, the signals A and B are broadcast and the directional signals VL and VR are regenerated at a receiver to effect stereophonic reproduction. Apparatus for deriving two compatible signals.-The left and right signals VL and VR, which may be derived from crossed directional microphones, appear in channels 1 and 2, respectively (Fig. 1). ). VL is applied to two summing circuits 3 and 4, directly in the case of 4 but through an amplifier of gain two in the case of 3, while VR is applied directly to 3 and 4. The output of 3 is therefore 2VL + VR and that of 4 is VL + VR. These two signals, which constitute the signals A and B, amplitude modulate a carrier wave from oscillator 8 in modulators 6 and 7, the filters 9 and 10 suppressing the lower and upper sidebands respectively, and the remaining sidebands being mixed at 11. Stereophonic reproduction from signals A and B.-The received signals are applied to filters 14 and 15 (Fig. 2), corresponding to 9 and 10 (Fig. 1), which select the upper and lower sidebands respectively and apply them to demodulators 16 and 17 to derive signals A and B. Signals A and B are applied to the differencing circuit 18 which produces A-B, namely VL Signal B is also applied via an amplifier 19 of gain two to the differencing circuit 20 where A is subtracted to produce 2B-A, namely VR. The signals VL and VR are amplified at 21, 22 and fed to spaced loud-speakers 24, 25. Modified arrangements.-In the arrangement of Fig. 3 (not shown) the signals VL and VR are applied to a circuit which produces a relative phase shift of 90 degrees between them to produce VL and jVR. These signals are added to produce A and subtracted to produce B. At the receiver (Fig. 4, not shown) the signals A and B derived by filtering and demodulating the sidebands are summed to produce 2VL and differenced to produce 2jVR, these signals then being passed through a circuit which produces a relative phase shift of 90 degrees between them to derive signals representative of VL and VR which are fed to the loud-speakers.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB3252258A GB931422A (en) | 1958-10-11 | 1958-10-11 | Improvements relating to stereophonic sound transmission systems |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB3252258A GB931422A (en) | 1958-10-11 | 1958-10-11 | Improvements relating to stereophonic sound transmission systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB931422A true GB931422A (en) | 1963-07-17 |
Family
ID=10339892
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB3252258A Expired GB931422A (en) | 1958-10-11 | 1958-10-11 | Improvements relating to stereophonic sound transmission systems |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB931422A (en) |
-
1958
- 1958-10-11 GB GB3252258A patent/GB931422A/en not_active Expired
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