GB939055A - A process for the production of polymeric materials - Google Patents
A process for the production of polymeric materialsInfo
- Publication number
- GB939055A GB939055A GB221659A GB221659A GB939055A GB 939055 A GB939055 A GB 939055A GB 221659 A GB221659 A GB 221659A GB 221659 A GB221659 A GB 221659A GB 939055 A GB939055 A GB 939055A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pulses
- circuit
- subcarrier
- transistor
- burst
- 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
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/79—Processing of colour television signals in connection with recording
- H04N9/87—Regeneration of colour television signals
- H04N9/89—Time-base error compensation
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Signal Processing For Recording (AREA)
Abstract
939,055. Automatic phase control systems; transistor circuits. AMPEX CORPORATION. Sept. 4, 1962 [Sept. 12, 1961], No. 33914/62. Drawings to Specification. Classes 40 (5) and 40 (6). In reproducing recorded colour television signals the subcarrier burst is gated out from the reproduced composite signal and used to generate pulses at positive-going zero cross-over points of the subcarrier cycles which then sample the instantaneous amplitude of sawtooth waves derived from a stable reference oscillator of frequency equal to the sub-carrier frequency, to produce a D.C. control voltage which acts on an electronically variable delay line in the path of the reproduced signals, for the duration of one line, to compensate and correct any phase errors. Further, a coarse D.C. phase control voltage may be added to the above fine control voltage, derived by comparing reproduced horizontal or other sync pulses with a reference pulse train of equal or related frequency. The cross over detector (i.e. pulse generator) may comprise a normally conductive transistor cut off by positive going half cycles of subcarrier burst (after limiting), to produce ringing in a resonant collector circuit limited to half a cycle by a shunt rectifier, thereby producing pulses with timing determined by the phase of the subcarrier. A similar cross-over circuit may be used for the sawtooth generator, pulses produced as above from a crystal oscillator charging through a transistor amplifier a capacitor whose discharge through a transistor emitter follower produces the sawtooth with subcarrier recurrence frequency. Feedback from the emitter output circuit to the capacitor discharge resistance produces a linearising bootstrap effect. The subcarrier frequency pulses and saw tooth are then respectively applied across and to the centre tap of a transformer secondary connected across the bases of a PNP and NPN pair of transistors, with emitters feeding a capacitor deriving the D.C. control voltage. The subcarrier burst is gated out by a delayed reproduced horizontal sync pulse whose trailing edge triggers a transistor blocking oscillator to provide a pulse, of burst width, transformer coupled to a diode ring bridge to open it and pass only the subcarrier burst from an applied composite reproduced television signal. The diode bridge is normally non-conductive due to being shunted by a circuit having normally conductive rectifiers but rendered non-conductive by the blocking oscillator pulses. A delay and gate circuit (Fig. 5, not shown) may act on the subcarrier frequency output pulses from the cross-over detector circuit so that the start and finish of the burst is dispensed with. In this delay circuit an emitter follower is energized by the blocking oscillator output pulses and a selected duration of the pulses is derived by a transistor amplifier having a tuned circuit; an input R-C circuit of the amplifier and the tuned circuit both producing a delayed output. Spikes and transients may be removed from negative going reproduced horizontal sync pulses by applying them to block a normally conducting series rectifier so that an R-C circuit discharges and after 2 Ásec. delay opens a normally blocked transistor until the negative sync pulses ceases, i.e. pulses of less than 2 Ásec. duration are eliminated but the timing of the rear edge of the transmitted sync pulse is unchanged.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB221659A GB939055A (en) | 1959-01-21 | 1959-01-21 | A process for the production of polymeric materials |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB221659A GB939055A (en) | 1959-01-21 | 1959-01-21 | A process for the production of polymeric materials |
Publications (1)
Publication Number | Publication Date |
---|---|
GB939055A true GB939055A (en) | 1963-10-09 |
Family
ID=9735642
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB221659A Expired GB939055A (en) | 1959-01-21 | 1959-01-21 | A process for the production of polymeric materials |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB939055A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1267704B (en) * | 1964-11-12 | 1968-05-09 | Fernseh Gmbh | Arrangement for compensating for the time error in a color television signal, in particular taken from a magnetic memory |
DE3114198A1 (en) * | 1980-04-08 | 1982-01-14 | Ampex Corp., 94063 Redwood City, Calif. | METHOD AND DEVICE FOR ELIMINATING PHASE ERRORS OF PAL BURST SIGNALS |
-
1959
- 1959-01-21 GB GB221659A patent/GB939055A/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1267704B (en) * | 1964-11-12 | 1968-05-09 | Fernseh Gmbh | Arrangement for compensating for the time error in a color television signal, in particular taken from a magnetic memory |
DE3114198A1 (en) * | 1980-04-08 | 1982-01-14 | Ampex Corp., 94063 Redwood City, Calif. | METHOD AND DEVICE FOR ELIMINATING PHASE ERRORS OF PAL BURST SIGNALS |
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