GB1509212A - Compatible am stereophonic transmission system - Google Patents
Compatible am stereophonic transmission systemInfo
- Publication number
- GB1509212A GB1509212A GB2772675A GB2772675A GB1509212A GB 1509212 A GB1509212 A GB 1509212A GB 2772675 A GB2772675 A GB 2772675A GB 2772675 A GB2772675 A GB 2772675A GB 1509212 A GB1509212 A GB 1509212A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signal
- difference signal
- amplitude
- phase
- frequency
- 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
- H04H20/44—Arrangements characterised by circuits or components specially adapted for broadcast
- H04H20/46—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95
- H04H20/47—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95 specially adapted for stereophonic broadcast systems
- H04H20/49—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95 specially adapted for stereophonic broadcast systems for AM stereophonic broadcast systems
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Stereo-Broadcasting Methods (AREA)
Abstract
1509212 Stereophonic broadcasting L R KAHN 1 July 1975 [10 July 1974] 27726/75 Heading H4R In a compatible amplitude modulated stereophonic broadcasting system a carrier wave is amplitude modulated with the sum of the stereophonically related signals and is phase modulated with a composite stereo difference signal formed of the fundamental difference signal together with a difference signal developed from the frequency doubled stereo related signals, the frequency doubled component being maintained in substantially square law relation relative the amplitude of the fundamental difference signal and about 13% of the fundamental signal amplitude at full stereo modulation. As described with respect to Fig. 1 L and R stereophonically related signals are applied to an adding network 12 to form a sum signal which, after shifting in phase by an amount #(f) -45 degrees provides a signal to amplitude modulate a transmitter carrier. In addition the L and R signals are fed through respective 5 kHz low pass filters to a subtractor 28 to provide a fundamental difference signal 30 which is passed through a network 32 to provide a phase shift of #(f) +45 degrees, i.e. +90 degrees relative the sum signal at 18. The filtered L and R signals are also fed via networks 38 and 40 having a phase shift of #(f)+0 to frequency doublers 46 and 48 before application to subtractor 54 to derive a frequency doubled difference signal 56. The signal 56 is applied through a variable gain amplifier controlled in accordance with the level of the fundamental difference signal so that the level of the signal 68 at the output of amplifier 58 is proportional to the square of the fundamental difference signal amplitude. The fundamental difference signal and the frequency doubled difference signal are combined at 36, the delay equalized at 72, and the combined signal phase modulates a carrier signal from oscillator 78 in modulator 76 before frequency multiplying to the appropriate broadcast frequency and amplitude modulating with the sum signal for broadcasting. A 15 Hz stereo indicator signal can be added either to the amplitude modulating signal or as a phase modulating signal. The resulting signal has the stereophonically related signals appearing respectively in the upper and lower first order sidebands.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US487155A US3908090A (en) | 1972-05-10 | 1974-07-10 | Compatible AM stereophonic transmission system |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1509212A true GB1509212A (en) | 1978-05-04 |
Family
ID=23934634
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2772675A Expired GB1509212A (en) | 1974-07-10 | 1975-07-01 | Compatible am stereophonic transmission system |
Country Status (4)
Country | Link |
---|---|
JP (1) | JPS5951183B2 (en) |
CA (1) | CA1038933A (en) |
GB (1) | GB1509212A (en) |
NL (1) | NL182188C (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH054515Y2 (en) * | 1987-03-16 | 1993-02-04 |
-
1975
- 1975-07-01 GB GB2772675A patent/GB1509212A/en not_active Expired
- 1975-07-02 CA CA230,618A patent/CA1038933A/en not_active Expired
- 1975-07-07 JP JP8334875A patent/JPS5951183B2/en not_active Expired
- 1975-07-08 NL NL7508131A patent/NL182188C/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
CA1038933A (en) | 1978-09-19 |
JPS5951183B2 (en) | 1984-12-12 |
AU8261175A (en) | 1977-01-06 |
JPS5132105A (en) | 1976-03-18 |
NL7508131A (en) | 1976-01-13 |
NL182188C (en) | 1988-01-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PE20 | Patent expired after termination of 20 years |
Effective date: 19950630 |