JPS5539439A - Stealthy glance preventing system for catv system - Google Patents
Stealthy glance preventing system for catv systemInfo
- Publication number
- JPS5539439A JPS5539439A JP11283178A JP11283178A JPS5539439A JP S5539439 A JPS5539439 A JP S5539439A JP 11283178 A JP11283178 A JP 11283178A JP 11283178 A JP11283178 A JP 11283178A JP S5539439 A JPS5539439 A JP S5539439A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- stealthy
- frequency
- horizontal synchronous
- preventing
- 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.)
- Granted
Links
Abstract
PURPOSE: To prevent the stealthy glance due to reception of the adjacent channels for the multi-channel CATV system by using the frequency of double as much as the horizontal synchronous signal to the modulation signal.
CONSTITUTION: Signal (a) generated from horizontal synchronous signal generator 1 pulse signal (b) received the 90° phase shift at phase shifter 2 are appied to video signal generators 31∼3n with application of GEN LOCK so that the output channels of converter 6 may be adjacent to each other. Both the output of the video modulator and the aural signal are modulated to the IF signals through modulators 41∼4n, and then the horizontal synchronous signal is detected at the stealthy glance preventing modulator. Then the AM modulation is applied so that the synchronous signals may be suppressed by the double frequency signal. And the horizontal synchronous signals undergo the frequency conversion through frequency converters 61∼6n and then added together at acarrier adder 7 to be sent to transmission line 8. After this, the demodulation is given at demodulation part 11 to suppress the stealthy preventing modultation component after the frequency conversion at terminal 9. Thus the adjacent channels cannot be demodulated since the phases of their synchronous signals differ from each other.
COPYRIGHT: (C)1980,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11283178A JPS5539439A (en) | 1978-09-13 | 1978-09-13 | Stealthy glance preventing system for catv system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11283178A JPS5539439A (en) | 1978-09-13 | 1978-09-13 | Stealthy glance preventing system for catv system |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5539439A true JPS5539439A (en) | 1980-03-19 |
JPS6156920B2 JPS6156920B2 (en) | 1986-12-04 |
Family
ID=14596619
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11283178A Granted JPS5539439A (en) | 1978-09-13 | 1978-09-13 | Stealthy glance preventing system for catv system |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5539439A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH071793U (en) * | 1992-12-09 | 1995-01-13 | 有限会社新津興器 | Thaw container |
-
1978
- 1978-09-13 JP JP11283178A patent/JPS5539439A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS6156920B2 (en) | 1986-12-04 |
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