Patent GB-1052948-A (GB)
IPC: H04N5/06
Abstract: 1,052,948. Television. ASSOCIATED TELEVISION Ltd. Nov. 15, 1963 [Nov. 19, 1962], No. 43647/62. Heading H4F. The invention comprises a system which distributes television pulse waveforms from a plurality of pulse waveform generators, some of which may operate on different scanning standards, to various positions in a group of television studios or outside broadcast units, said pulse waveforms being formed by combining the various synchronizing and blanking pulses, or timing pulses representing the leading edges of the synchronizing and blanking pulses, into a composite pulse waveform and means being provided at the said various positions for separating and regenerating from said composite pulse waveform the synchronizing and blanking pulses required for picture generating equipment. Fig. 1 shows on the left one of up to five pulse waveform generators 1 and on the right one regenerator circuit located in one of the studios. The composite synchronizing and blanking signals from generator 1 are resistively combined at the output of the transistor combining circuit 2 by the resistive signal dividing network 3, the combined pulse waveform being shown at W. This signal is fed to one pole of a fiveposition selector switch 4, the other poles being attached to other television pulse waveform generators (not shown), and then over the coaxial line 5 to the regenerator circuit where it is applied to the blanking pulse separator 6 and synchronizing pulse separator 7. The leading edge of the pulse output from synchronizing pulse separator 7 is fed through an inverter stage 8 to trigger multivibrator 9 the output of which triggers multivibrator 10 which provides the line drive signal after amplification. The composite synchronizing signal is also fed through a delay device 12, an emitter follower 13 to an output amplifier 14 to provide the composite synchronizing signal output. The composite blanking signal is fed through delay device 15, emitter follower 16 and inverter 17 to an output amplifier 18 to provide the composite blanking signal. The output of multivibrator 19, which is triggered by the leading edge of the blanking waveform at the output of emitter follower 16, is connected to one side of coincidence gate 20 the other side of which is fed with the composite blanking signal. The output of gate 20 is fed via inverter 21 to trigger a multivibrator 22 which forms the field drive pulses. The Specification states that one common pulse duration for each of the line and field drive signals may be used on all of the scanning standards provided the leading edges are correctly located in relation to the remainder of the pulses. Burst gating pulses are generated by control pulses derived from the leading edge of the line drive signals which are fed through a delay circuit 24 and which are gated out by the appropriate field waveforms in circuit 25 to control the burst gate pulse generator 26, whose output is fed through amplifier 27. In an embodiment (Fig. 2, not shown) two outside broadcast camera units are combined so that all the cameras operated by both units are in synchronism, only one of the units having a pulse waveform generator the other having a regenerator circuit as described with reference to Fig. 1.