U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

Matthias Peters

Jorg Wolber

Klaus G Kroner

Hartmut S Harlos

Gerd Onken

Christian Brun

Methods and apparatus are described for time-correct combination of two data streams, particularly video data streams. In this case, a sync signal of the first video data stream is a horizontal sync signal. In this case, methods and apparatus are provided to combine the two video data streams in a pixel-precise manner, even though time base error, i.e. discontinuities occur in the second video data stream.

Arrangement for time-correct combination of two data streams

Circuit arrangement for controlling a picture display tube

A circuit arrangement for amplitude-dependent attenuation of a television signal supplies amplitude values below a predeterminable limit value as an output signal amplified by a first gain factor, and, at amplitude values above the limit value, supplies the part of the amplitude below the limit value as an output signal amplified by the first gain factor and parts of the amplitude above the limit value as an output signal amplified by a second gain factor, the second gain factor being chosen to be smaller than the first gain factor. To realize this circuit arrangement in the current range, the television signal is a current signal which is applied to a main branch (1; 13) and a sub-branch (2; 14) in which the current signal is applied to the emitter of at least one transistor (3,5; 15,18) via a resistor (4,6; 16,19), the base of each transistor (3,5; 15,18) is biased with respect to a reference potential by DC sources (7,8; 17,24), the collector current of the transistor (3; 15) in the main branch (1; 13) essentially represents the output signal, and the limit value is predeterminable by the difference between the base potentials of the two transistors (3,5; 15,18) and the second gain factor is predeterminable by means of the resistance ratio between the two resistors (4,6; 16,19).

Circuit arrangement for amplitude-dependent attenuation of a television

A circuit arrangement for processing an input video signal (V) is described, which video signal has a fixed black level (SP), a given white peak value (WW) as well as a black peak value (SW) dependent on the picture contents (during tb), in which a correct display of the blackest and brightest parts of the picture contents of the video signal (V) is rendered possible without many components and without interference. To this end the circuit arrangement includes

Contrast and brightness control whereby both are based on the detected

Circuitry for processing, in a television signal, a first, low-frequency synchronizing signal on which a second, high-frequency synchronizing signal is superposed, for supplying standardized television signal capable of being processed by a customary television signal processing arrangement or display device, respectively by inhibiting a shift between the picture content of the signal representing the television signal and the synchronizing signal. The circuitry includes a first signal processing branch (1) having a low-pass filter (11) for separating low-frequency components and consequently the first synchronizing signal (Sy1) from the television signal, a synchronizing pulse detector (12) for detecting signal variations exceeding a cut-off level (SP) in the low-frequency components, and also a pulse generating stage (13) for producing a pulse when such a signal variation corresponding to a synchronizing pulse of the first synchronizing signal (Sy1) is detected, the pulse being of a duration shorter than the shortest second synchronizing signal (Sy2), a second signal processing branch (2) having a halfwave detector (21) for separating signal peaks exceeding maxima (MaSy1) of the first synchronizing signal (Sy1) from the television signal and for charging a signal store (23) in a first direction during a time interval corresponding to the period of the second synchronizing signal (Sy2), in which the signal peaks occur, and also a third signal processing branch (3) producing a constant reference level during a time interval wherein either a pulse is supplied in the first signal processing stage (1) or the signal store (23) is charged in the first direction, instead of the television signal produced in the remaining time.

Circuitry for processing a synchronizing signal

A single pin oscillator which consists of first and second transistors (17, 18) whose collectors are connected, via respective collector resistances (19, 20), to the positive pole of a DC source U.sub.V and whose emitters are connected to the negative pole thereof via respective emitter resistances (21, 22). The collector of each transistor is connected to the base of the other transistor. A quartz crystal (12) or a series resonant circuit is connected to the emitter of one transistor (17) and parallel to the corresponding emitter resistance (21). A driver circuit (23) is provided for an oscillator voltage which can be coupled out to an external low-ohmic, highly capacitive load connected to the emitter of the other transistor (18) and parallel to the corresponding emitter resistance (22).

Growing community of inventors

Neu Wulmstorf, Germany

Matthias Peters