Video Delay Line Research Articles

Circuit theory of video delay lines

Electromagnetic slow waves guided by single-layer coils and video delay lines are studied from the point of view of circuit theory. The main idea is to introduce into the model the mutual inductance that exists between nearby coil turns. This concept leads to finite-difference, finite-sum equations which pass in the limit into a partial differential equation and an integro-differential equation. The capacitance between adjacent wire turns is taken into account. The decrease of inductance at high frequencies, as computed from the integro-differential equations, is compared with prior computations based on electromagnetic field theory. In this respect agreement between the two theories is complete. A comparison with experiment is made, from which a novel parameter of the coil, termed the series capacitance parameter and measured in Fm, is determined.

A CCD video delay line with charge-integrating amplifier

The authors describe a charge coupled device (CCD) sense amplifier in a video delay line which overcomes the major limitations of conventional floating diffusion amplifier (FDA) technology, such as limited output voltage and operating temperature range. These advances are implemented with a switched-capacitor integrator (SCI) using an op amp with a newly developed output stage in a CMOS-CCD process. This circuit is effected within the constraints of 5-V operation by using negative pulses to reach the low channel potential of the CCD in the pinning region in the final gate of the CCD. The chip operates with 14.3-MHz clock and 5-V power supply, and can process a 1.0-V/sub p-p/ signal voltage under 1% distortion, and under 4% gain variation from -20 to 70 degrees C. >

A compact TV ghost generator

A TV ghost generator that does not use long cables to achieve the desirable time delay is described. Instead it makes use of a video delay line and two synchronized modulators. The design of the generator is described, and test results are presented. This ghost generator provides a low-cost and convenient-to-use instrument for testing the ghost cancellation capabilities of TVs being developed or produced.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A T.V. Type of Analogue Image Processor

A T.V. type of analogue image processor using a scan-converting storage tube is described. In this processor, the pictures pre-processed by video delay lines and multipliers in an image-serial and aperture-parallel manner are superimposed successively on the target surface of the tube in an image-parallel and aperture-serial manner. It is shown theoretically and experimentally that when the image-serial and aperture-parallel pre-processing is applied to the well-separated groups of subdivided aperture-weights, the above processing method becomes very effective. Some experimental results of restoration of defocused images are presented, showing that the quality of restored images is comparable with those obtained by digital computer.

64 Stage BCD (Bulk Charge-Transfer Device) Analog Memory with Differential Integrated Clock Pulse Generator

A 64 stage BCD (Bulk Charge-transfer Device) with a new differential integrated clock pulse generator is developed. The device effectively eliminates problems of interference from external clock pulse circuits to a picture tube, and of output voltage variation in varying clock pulse frequency of a conventional device. The BCD consists of two clock pulse circuits fabricated differentially to drive two arrays separately. Experimental results show good matching of the two arrays. In addition, the device requires only one TTL level master pulse and two power supplies, thus enhancing its application to practical video delay lines.

A wide-band low-noise charge transfer video delay line

A new wide-band low-noise charge transfer video delay line is introduced utilizing a bulk charge transfer device (BCD) with a self-aligned electrode structure, and a simple integrated sample-hold circuit. Brief analysis of charge transfer characteristics of the BCD and design considerations for the proposed device are included. Several kinds of 128-element devices are designed and examined. Measured transferred signal bandwidth is 4 MHz at 10 MHz clock of voltage swing as low as 10 V, with signal-to-noise (S/N) ratio of 42 dB. The device itself can operate beyond 20 MHz clock rate. Moreover, the device features the use of an elaborate sample-hold circuit to eliminate the complex reset pulse and filtering circuitry, high packing density of 18 /spl mu/m per element with 3-/spl mu/m line spacings assuring a high fabrication yield, and process compatibility with conventional Si gate MOS technology.

A V-groove oxide isolated bipolar bucket brigade shift register

A V-groove oxide isolated bipolar bucket brigade shift register structure is described in this paper. The operation of the shift register is analyzed to determine the frequency and transfer efficiency limitation and point out the inherent advantages of such a structure. Measurements carried out on experimental 36-stage V-groove BBD registers are presented to demonstrate the capabilities of the devices. The proposed V-groove BBD structure results in registers with higher operating frequencies and greatly increased packing density when compared to standard junction isolated devices. These improvements are obtained without sacrificing the low or mid-frequency response and make these devices useful in video delay line applications.

The design of a precision video delay line

The paper reviews briefly the very stringent conditions which must be fulfilled by video delay lines connected in a television programme chain. The most suitable method of construction is found to be a cascade of delay sections of the same image impedance, and three types, onebelieved to be novel, are examined in detail with respect to their suitability for long delays inserted in main signal-handling paths. It is concluded that the advantage lies with low-pass sections combining pairs of complex conjugate m values in an appropriate configuration. These offer a markedly improved performance compared with conventional methods of construction, together with a substantial reduction in the number of inductors for a given delay over the video band. Guide lines for the design of video delay networks are laid down, and methods of compensationfor component dissipation are discussed in some detail. The performance of a prototype 1 μs delay line built on these principles has fully confirmed the theoretical findings.

Synchronization of Remote Program Sources for Color TV Broadcasting

For program integration all video sources must be in raster phase as well as in color phase. The usual color genlock technique permits the integration point to be in phase with only one of the sources at a time. Dissolves, special effects, etc., between any two remotes are therefore impossible. The Remote Sync System permits all of the remote points to be color- and raster-phased semiautomatically. Color and raster phase is available for a fixed time after the remote has been “talked-in.” Using an automatic video-delay line at the integration point and using highly stable subcarrier oscillators, the system provides hours of color and raster phase. This time can be even further extended if occasional manual corrections are made at the remote point or at the integration point.

A Simplified Television Color Encoder

A simplified NTSC-compatible encoder produces a signal which is subjectively equivalent to that of a full broadcast encoder but is simplified to the point of requiring only one 6- by 8-in. printed circuit card. The red, green and blue (R, G, B) signals are matrixed into the R–Y and B–Y chrominance signals. The bandwidths of both signal paths are identical, thereby eliminating the need for an additional video-delay line. Moreover, the burst-flag signal is added negatively to the B–Y signal before band limiting; therefore, no special delay is needed for the burst flag. The R–Y and B Y signals are modulated in balanced fashion with the color subcarrier 90° out of phase. The subcarrier is generated internally by a crystal oscillator. An external subcarrier from a crystal-controlled source can also be used. To create the Y signal, the R, G, B signals are matrixed in the normal manner after which the “combined” signal is amplified and inverted. The inverted Y signal is added directly to both the R and B signals simultaneously in correct proportions, thereby creating the R-Y and B-Y chrominance signals. A separate luminance channel has also been incorporated; this enables a separately derived luminance signal to be used directly as the Y signal. The output of the encoder is a composite color video signal completely compatible with receivers designed for the NTSC signal.

A true i.f. logarithmic amplifier using twin-gain stages

A true i.f. logarithmic amplifier is described which avoids the successive detection principle and its associated video delay line. Each stage comprises a pair of long-tailed pairs in a complementary role. Transistors are used throughout but ‘bottoming’ is avoided, and bandwidth variations are negligible. A dynamic range of about 100 dB is possible. A video output may be derived if desired from a single detector after the last stage, but when an output at i.f. is taken, phase variations with amplitude may be of interest, and have been investigated. A technique for correcting such phase variations is described, and a development of the basic amplifier circuit is given which should minimize such phase variations at their source.

A compact video delay line

An improved design of distributed parameter video delay line is discussed in which small size is achieved with better frequency and time domain characteristics. The device consists of the tandem connection of unit sections each of which is a distributed delay line of proper length using ferrite cores both inside and outside of the coil. This construction permits larger diameter of delay line with improved transfer characteristics, and consequently larger time delay can be obtained in shorter length. The experimental results show that a 1 μS delay line with 3 Mc bandwidth is constructed for about 2 inch length with little waveform distortion.

Minimizing the Effects of Vidicon Lag with a Long Video Delay Line

Minimizing the Effects of Vidicon Lag with a Long Video Delay Line

A Simple Method of Phase Compensation of Video Delay Lines

A Simple Method of Phase Compensation of Video Delay Lines

The Compensation of Delay Distortion in Video Delay Lines

Delay distortion in ordinary solenoidal delay lines is primarily caused by the decay of solenoid inductance resulting from a reduced magnetic coupling at the higher frequencies. An analysis of the phase characteristic of delay lines which employ solenoid bridging capacitances to compensate for this inductance variation is presented. The relations necessary for determining the delay distortion and effective bandwidth corresponding to any amount of compensation are given. The analysis is verified by observations on several experimental lines, wherein the bridging capacities are obtained by means of isolated metal patches placed in proximity to the solenoid.