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(12) Patent: | (11) CA 1207430 |
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(21) Application Number: | 1207430 |
(54) English Title: | VIDEO SIGNAL IMPOSE CIRCUIT |
(54) French Title: | CIRCUIT DE COMBINAISON DE SIGNAUX VIDEO |
Status: | Term Expired - Post Grant |
(51) International Patent Classification (IPC): |
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(72) Inventors : |
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(73) Owners : | |
(71) Applicants : | |
(74) Agent: | SMART & BIGGAR LP |
(74) Associate agent: | |
(45) Issued: | 1986-07-08 |
(22) Filed Date: | 1984-02-23 |
Availability of licence: | N/A |
Dedicated to the Public: | N/A |
(25) Language of filing: | English |
Patent Cooperation Treaty (PCT): | No |
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(30) Application Priority Data: | ||||||
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ABSTRACT OF THE DISCLOSURE
Disclosed is an arrangement for combining video signals from two
sources, for example a TV signal and a signal from a computer. Known arrange-
ments of this type mute the first signal and then insert the second signal
but, because of the response time of the muting circuitry, the composite
picture displayed on a cathode ray tube is defective in that it includes a
white or black band. In this invention, the output of a demodulator for
the first signal is connected to a series circuit of a resistance and an
open collector type inverter so that the resistance lowers the cutoff level
of a transistor constituting a buffer amplifier to which the demodulated
first video signal is fed. The operating point of the transistor is kept
always in an active region so that startup of the transistor is rapid to
enable high speed response of the buffer amplifier, thereby improving the
quality of the composite picture displayed on the cathode ray tube.
Note: Claims are shown in the official language in which they were submitted.
Note: Descriptions are shown in the official language in which they were submitted.
Sorry, the representative drawing for patent document number 1207430 was not found.
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Description | Date |
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Inactive: IPC expired | 2023-01-01 |
Inactive: IPC from PCS | 2022-09-10 |
Inactive: IPC from PCS | 2022-09-10 |
Inactive: First IPC from PCS | 2022-09-10 |
Inactive: IPC expired | 2011-01-01 |
Inactive: IPC from MCD | 2006-03-11 |
Inactive: Expired (old Act Patent) latest possible expiry date | 2004-02-23 |
Grant by Issuance | 1986-07-08 |
There is no abandonment history.
Note: Records showing the ownership history in alphabetical order.
Current Owners on Record |
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None |
Past Owners on Record |
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YUZO KAWAHARA |