The Philips LDK 3 is a third-generation Plumbicon Colour Camera for studio and outside broadcast use.

It represents a major advance in camera design, based on many years of successful experience with previous versions of three-tube Plumbicon colour cameras.

The latest colour television techniques and modular system lay-out have been employed to ensure high stability, reliability, and flexibility in operation.

• Three-tube camera with integrated "contours-from-green" principle for true colour and lifelike sharpness.
• Separate-mesh Plumbicon tubes for better overall resolution and excellent high-light handling.
• More efficient prismatic colour beam-splitting system and linear matrixing for optimum colorimetric response.
• Utmost flexibility in camera optics.
• Diascope lens attachment projects test pattern directly into camera for setting-up.
• Dynamic focusing for better overall picture sharpness.
• Modular type CCU in three separate sub-assemblies for high operational flexibility.
• Integral encoder and colour bar generator for "vector-scope-less" encoder adjustment
• Built-in test sawtooth and bridging facility for short video lining-up time.
• All-silicon circuitry for exceptional stability and "hands off" operation.
• Outstanding mechanical precision and rigidity.
• Full remote control facilities.

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Its precision lens-mounting allows the application of optical systems and drive systems using the latest techniques.

The wide range of high-quality zoom lenses available from the leading lens manufacturers includes fully servo-controlled lenses, as well as lenses with manually-controlled focus and zoom and servo-controlled iris.

The majority of these lenses accept range extenders. Zoom and focus demand units can be attached to the panhandles, the iris being controlled from the CCU or any remote position.

The servo amplifiers are located either in the camera or in the lens package, depending on the type of lens employed. Two independent motor-driven filter wheels are provided between lens and colour beam-splitter, one for colour-correcting filters and one for neutral density filters.

Selected from the CCU or any remote position, these filters serve for an instant matching of the camera to sudden changes in colour temperature or light input, such as are liable to occur in outside broadcast operation.

The colour beam-splitting system is the well-known prism-block with its two internal reflections per channel. It consists of three small glass prisms cemented together in such a way that the dichroic reflecting layers are fully protected.

The introduction of linear matrixing allowed the use of a more efficient colour beam-splitting prism.

Apart from the signal amplifiers, the camera electronics comprise the following circuits:
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• horizontal time base and blanking generator
• dynamic focusing
• internal test signal generator
• scan failure protection
• regulated power supply
• signalling
• intercom amplifier
• servo amplifier for the lens drive system (with certain types of lens).

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The circuitry of this unit has been divided into functional sections and arranged in small modules of two sizes: the single module, one-twelfth of a 19-inch rack width; and the double module, one-sixth of this width. These modules, which are arranged in two rows in the unit, contain the circuitry for: video processing, including contour enhancement, pulse generation and timing, vertical scanning, focusing and beam alignment, picture switching, test signal generation, communication, signalling and remote control.

The Electronics Unit includes an encoder in accordance with the PAL or NTSC standard, and a colour bar generator for either the CCIR or EIA scanning system. The delay module of the contour extractor is also available in two versions, for the CCIR and EIA system respectively.

The unit also has two spare locations lodging module extenders. Advanced video processing techniques have been employed to ensure outstanding precision and stability of performance. The processing channels, therefore, include the following stages:

• cable length compensation (for a camera cable length up to 1000 metres)
• spurious pulse cancellation
• green tilt correction (green camera channel only)
• master gain switching
• colour balance switching (or painting)
• white clipping
• automatic black level control
• horizontal and vertical contour enhancement
• linear-matrixing for negative lobe compensation
• horizontal aperture correction (also usable as notch filter for noise reduction around the sub-carrier frequency)
• white limiting (adjustable to  "sharp" and "soft" operation)
• adjustable gamma correction

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The processing amplifier channels put out 5 sets of R, G, B gamma corrected signals (0.72 V into 75 Ohm) for monitoring, encoding and external use, as well as 1 set of R, G, B non-gamma-corrected signals for video testing. Either a saw-tooth signal from the test signal generator in the CCU, or an external test signal, can be switched to the video processing channels.

The remote control module is equipped with a meter and selector for monitoring all the power supply voltages, and with tally lights for power supply and scan failure indications. The camera chain is provided with a standard intercom system, but other systems can be employed, if required. The waveform monitor switch module provides a NAM (non-additive-mixed) signal, built-up from the largest amplitude and the lowest black-level information given by the red, green and blue video signals. This signal can be used for "simple" waveform control systems, automatic exposure control circuits, or "centralised camera matching".

supplementary:
6. test signal (VB, monochrome saw-tooth or grid-pattern),  + 0.7 Vpp across 75 Ohm (loop-through sockets), for lining-up the video processing channels.
7. external picture signal (VB, monochrome), + 0.7 Vpp across 75 Ohm, as over-lay signal on the picture monitor and/or camera view-finder. 8     external picture signal (VB, mono-chrome), + 0.7 Vpp across 75 Ohm (loop-through sockets), as over-rule signal on the picture monitor and/or camera view-finder.
Output signals
1. 2 x R, G, B gamma-corrected signals (VB), 0.7 Vpp across 75 Ohm, of which 1 set is intended for Colour Waveform Monitor LDK 4910/00.
2. 2 x R, G, B non-gamma-corrected signals (VB), 0.7 Vpp across 75 Ohm, to be used for video testing.
3. video signal (VBS), 0.7 Vpp across 75 Ohm, pre-selected for the picture monitor by switch on the Local Control Panel.
4. NAM (non-additive-mixed )signal, 0.7 Vpp across 75 Ohm, built-up from
largest amplitude and lowest black-level information from the R, G, B camera signals. To be used for "simple" control systems, automatic exposure control circuits, or "centralised camera matching".
5. 2 x composite colour signal (VBS), nominal 1 Vpp across 75 Ohm.
6. 1 x composite colour signal without sync (VB), nominal approx. 1 Vpp across 75 Ohm.
7. 2 x composite sync signal (S), 4 Vpp negative going, across 75 Ohm.

Scene illumination
1500 Lux (150 ft. cd.) for a signal-to-noise ratio > 40 dB in the Y-signal from the encoder at a signal level of 0.7 Vpp; with a reflection factor of the scene 0.6; with a signal current of 225 nano-Amp. in Green; lens iris set to f/4; master gain set to 0 dB; level-dependent aperture correction set to 6 dB at 5 MHz: gamma correction set to 0.6;
5 MHz signal bandpass; with contour enhancement operating at 60 % of maximum boost.
250 Lux (25 ft. cd.) for just acceptable pictures; with the lens iris set to f/2.2.

Resolution
With aperture correction, 100% modulation depth can be obtained at 5 MHz in each video channel.
Registration accuracy Deviations of Red or Blue in any direction with respect to Green
In area I, being the ellipse in the centre of the scanned picture with axes 0.9 of picture height and width, deviations will be no more than the distance equal to a horizontal scanning time of 40 nanosec.
In area II, being that part of the scanned picture outside area I but within a circle having a diameter equal to the picture width, deviations will be no more than 80 nanosec.
In area III, being that part of the scanned picture outside area II, deviations will be no more than 120 nanosec.

Registration drift
Deviations of Red or Blue in any direction with respect to Green
A.    Variations of the ambient temperature of the camera of no more than ± 10°C from the temperature during registration setting (within the range of —10 to +45°C) will not cause mutual picture shifts larger than 50 nanosec.
B.    External magnetic fields, not exceeding a field strength of 1 Gauss, will not cause additional registration errors of more than 25 nanosec within area I when the camera is moved or turned in any direction.
C.    Mechanical shocks, such as occur during normal camera operation, will not have any influence on the picture registration.

Picture geometry
Maximum horizontal and vertical geometric distortion is 0.5 % of the picture height within area I (see colour registration). In the remaining picture area, maximum distortion is 1 % of the picture height.
Signal-to-noise ratio
Measured at a signal current of 300 nanoAmp.; without aperture correction, contour enhancement, and gamma correction. Within a video bandwidth of 5 MHz and measured at 40 % of peak white, the signal-to-noise ratio will be better than 45 dB, in each channel.
Contrast range
Each video channel can handle a contrast range of up to 60 : 1.
Gain control
Master selector for —6 dB; 0 dB; and + 6dB; individual control for ± 3 dB in each channel.
Painting control
± 2 dB in Red and Blue (before gamma correction).
Frequency amplitude response for processing amplifiers
Flat to within ± 0.5 dB at up to 5 MHz, —3 dB at 7 MHz, for each video channel, with minimum aperture correction.
Low frequency response
Tilt ^ 0.25 %/ms.
Aperture correction
In each channel, preset for amplitude boosting of maximum + 10dB at 5 MHz, and preset for amplitude threshold beyond which correction starts, adjustable between 0 and
 100 % of white level. This circuit can be switched to the function of notch filter for noise reduction between 4 and 5 MHz.
Gamma correction
3-step selector for: linear operation, gamma = 0.35 to 0.6 (with preset adjustment),
gamma = 0.6 to 1 (with preset adjustment).
Gamma tracking at peak white level will be ^ 0.5 %, and near black level ^ 0.25 %, with respect to the gamma curve in the green channel.
Black-level adjustment
Master control for adjustment between —40 % and +50 % of the nominal white level.
Individual control in each channel for adjustment between —15% and + 15 % of the nominal white level. Automatic black-level compensation is provided in each video channel to minimize black-level shift due to optical flare.
Contour enhancement
Controls:
"S-correction" for minimum noise.
"Zero balance".
Preset adjustments:
for "H-V balance" (balance between horizontal and vertical contours).
for Hor. and Vert, contour symmetry. Amount of contour enhancement'
variable up to 0.7 Vpp for a pulse with a risetime of 100 nanos.
Camera cable
Standard camera cable is Felten & Guilleaume, type 756-1.
Minimum length 50 metres; maximum permissible length 1000 metres. Switchable compensation circuits are incorporated in the CCU for the above-mentioned single camera cable to a maximum length of 1000 metres.
Magnetic interference
No loss of performance in fields of up to 1 Gauss.
Acoustical noise
The acoustical noise level generated by lens controls and lens driving mechanisms will not exceed 30 dB at any position outside a 1 metre radius from the camera head.
Warming-up period
For the performance data specified, a warming-up period of 30 minutes should be taken into account. After a warming-up period of 2 minutes, excellent colour registration will be obtained.
Permissible ambient temperature
No change in performance data will occur at ambient temperature variations of ± 10°C with respect to the temperature during the line-up procedure, within a range of —10 to + 45°C.
Dimensions
See dimensioned sketches.
Weight
Camera without lens, servo amplifier or power supply unit: 42 kg.
Camera with zoom lens EL 8682/01, Angenieux 10x18.11, and complete servo control equipment: 75 kg.
CCU (Electronics Unit) in cabinet, complete with encoder and colour bar generator: 34 kg.
Local Control Unit, without waveform monitor: 16 kg (with waveform monitor 36 kg).
Power Supply Unit, without ventilator unit: 29 kg.

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