Showing papers on "Transmission delay published in 1970"

System for correcting time-base errors in a repetitive signal

Abstract: A system for correcting the phase of a substantially repetitive signal with respect to a known reference timing signal by providing a controlled variable delay of the former, in which a plurality of delay lines having binary ordered delay periods are interconnected by switching means, operating on command, to selectively cascade certain combinations of the delay lines and thereby provide a desired composite delay for each successive cycle of the repetitive signal. The system is particularly suited for providing extended delay range capability for synchronizing the phase of a television signal with a local reference signal. For this purpose, the total composite delay is selected to equal a basic period of repetition of the signal and the switching means interconnecting the delay lines is conditioned to operate during a synchronizing pulse waveform carried by the video signal, thereby avoiding the introduction of undesirable switching transients into those portions of the signal carrying analog picture information. In combination with the switched, binary ordered delay lines, circuitry is shown for developing a digital word signal representing the phase error for each cycle of the repetitive signal.

Transmission delay and echo suppression

Abstract: We are all aware that radio communication is not instantaneous. With the coming of satellite communication we have fallen prey to some of the consequences of telephony with long propagation time. So it is that when one person speaks to another via satellite link, he must wait perhaps 600 ms for a rejoinder. Such a delay, of itself, may not be too disconcerting, but in combination with echo it can contribute to poorer quality transmission. This is an account of how echo is produced, how it can affect a telephone conversation, and what steps are being taken to overcome the problems.

Automatic equalization system for data transmission channels

Abstract: A system for equalizing the phase distortion of a data transmission channel is disclosed wherein the equalizer comprises a fixed delay network and a plurality of selectable delay networks. The fixed delay network exhibits an envelope delay similar to the difference between the characteristic envelope delay for the channel and a desired delay for the channel and the selectable delay networks may be connected therewith in any combination to produce the desired envelope delay. Control means are provided for successively connecting the selectable delay networks to form a successive plurality of test channels. The phase distortion produced by each channel is measured and compared with that produced by each other test channel. The control means includes means for reconnecting the combination of selectable delay networks which produce the smallest value of phase distortion to provide equalization of the channel for data transmission.

Time delay equalizer utilizing a plurality of cascaded directional filters

Abstract: This application discloses a microwave delay equalizer which utilizes a cascade of directional filters interconnected by delay networks. Control of the delay characteristic is achieved by appropriately selecting the center frequencies and response characteristics of the filters and the delay times of the interconnecting delay networks.

Correlation radar system

Abstract: A correlation radar system utilizes a switching logic circuit for automatically switching a code word having a predetermined number of bits directly to a transmitter and through a delay to a receiver of the system and, alternately, directly to the receiver and through a delay to the transmitter. By utilizing the switching circuit, the delay need only produce up to one-half the number of bits in the code word.

The Design of Optimal Third-Order Bang-Bang Systems Using Delayed Switching

Abstract: The time optimal performance of bang-bang control systems can be achieved by properly timing the relay operations, two switchings being required for the optimal response of third-order systems. The movement of the state point is observed in the two-dimensional projections of the phase space. If the first switching is delayed after the state point has crossed the optimum curves in both planes, the second switching occurs at the optimum switching boundary. The coordinate axis and the optimum boundary divide the phase space into sections described by logic variables, from which the controller has been developed. A function generator determines the projections of the optimum switching curve, and a delay circuit is designed to delay the first switching operation.

Measurement of time delays in multipath systems

Abstract: In a recent letter, Gouriet proposed a method of measuring time delay, which uses the fact that the time delay of a linear system is the group delay at zero frequency. Based on the same method, a system is proposed in this letter to measure the time delays in a linear system which provides more than one transmission path between a single output and a single input. The system assumes that a rough knowledge of the magnitudes of time delays is available and that the individual multipath responses do not overlap in the time domain.