Abstract: A signal correction circuit for correcting deviating pixel values includes a part (113, 117) for comparing a first pixel value (R.sub.orig) of a given pixel with a second value (R.sub.filt) obtained from pixel values of pixels surrounding the given pixel so as to supply a decision signal (decR) if a predetermined criterion is satisfied; and a multiplexer (115) coupled to the above-noted part (113, 117) for supplying the second value (R.sub.filt) if the predetermined criterion is satisfied for not more than one color (R,G,B), and for supplying the first pixel value (R.sub.orig) in the opposite case.

Abstract: A color television encoding circuit suitable for use in a color television system in accordance with the NTSC or the PAL-standard. For the purpose of readjusting both the frequency and the phase of the line oscillator the circuit comprises only one control loop incorporating a phase comparison stage for detecting the difference of the phase of the chrominance subcarrier in the chrominance signals with respect to its zero value at the instant at which the leading edge of the synchronizing pulse reaches half the amplitude thereof. The output signal of the phase comparison stage is sampled once in every 2n line periods, where n is an integer, which results in the control signal for the line oscillator.

Abstract: NTSC-color television coding circuit comprising a series arrangement formed by a color difference signal matrix circuit, an I-signal and Q-signal matrix circuit, two low-pass filters, a modulator circuit and a superposition stage for supplying a quadrature-modulated chrominance signal. In order to obtain the chrominance sub-carrier burst in the chrominance signal, a burst-gate signal the pulse leading edge of which is produced before the beginning of the burst, is added to the -(B-Y) color difference signal. The chrominance signal in which the prolonged burst is distorted at the beginning by the filter is applied to a signal blanking circuit in which the distorted beginning is blanked and the burst in accordance with the standard is present in the chrominance signal obtained. Now, the burst amplitude can be adjusted, without a phase shift, by means of one potentiometer.

Abstract: A camera system for color television comprising a color television camera, a control unit and a signal processing circuit. As hue signal the signal processing circuit produces a composite color difference signal p(R-Y)+q(B-Y), wherein p and q are combination factors, R and B are color signals and Y is a luminance signal. In addition to the fact that this hue signal can be employed in known manner for chroma keying signal generation it is employed in accordance with the invention to check the registration on display. Herein, there is a choice between three fixed combinations of the combination factors p and q, the signal processing circuit producing a difference signal R-G, R-B and B-G, respectively. For the standardized luminance signal Y=0.59G+0.30 R+0.11 B it follows that: p=8q, p=-q and 7p=3q, respectively.

Abstract: An encoding circuit for a SECAM color television transmitter having a frequency modulator circuit for a modulating signal which comprises two color difference signals which follow one another line-sequentially and are controlled by means of two phase control loops and two reference signal generators. A first reference signal generator has one of the reference frequencies whereas the frequency of the signal generated by the second reference signal generator is a harmonic of the line frequency. The phase control loop to which the second reference signal generator is connected comprises a sample and hold circuit which is operative at field frequency.

Abstract: A circuit arrangement in a color television encoder comprising a first oscillator for generating a chrominance subcarrier signal, a second oscillator for generating a signal having the line frequency or a multiple thereof and a phase control loop for readjusting the phase of one of the said oscillators and including a sample and hold circuit operative every 2n.sup.th line and at a given instant in the line period, n being an integer. As a result thereof the phase between the two signals is fixed.

Abstract: A switchable synchronizing-signal generator suitable for several television standards, information being supplied from a series arrangement of a clock pulse generator and frequency dividers to a synchronizing signal generator. The generator has a position for the N-standard which is a modified position for the M-standard, because the supply of pulses of double the line frequency to a divide-by-525 dividers is blocked during 50 line periods of each field period.

Abstract: A circuit for increasing, mainly near a reference level, a signal slope of a periodically occurring signal, particularly at the black level of a television picture signal. To this end the gamma-corrected and limited luminance signal is applied in a color television camera to a first input of a differential amplifier, a second input of which is connected to a reference potential, the amplifier output being connected via a signal limiting circuit arranged in series with a first and a second resistor, respectively, to the first amplifier input and the reference potential, respectively. The junction of the resistors supplies the correction signal which increases the signal slope but does not effect either the black level or the peak-white value.

Abstract: A portable television camera and tape recorder combination wherein, prior to recording a scene, the signal of a bar generator is first recorded on a tape for test and reference purposes. After the preparations for recording the scene, wherein use is made of a view finder, the bar generator must be switched off and the camera signal must be recorded on the tape. By way of non-disturbing indication in the image on the view finder that the bar generator is switched on, the signal thereof is added, after differentiation, to the camera signal and displayed on the view finder.