Norman W. Parker

Stereo presence signal for an AM stereo system

In an AM broadcast transmitter, an infrasonic tone is added to the difference channel of a compatible AM stereo system to provide a stereo presence signal. In a stereophonic receiver, the corrected output of a synchronous detector in the difference signal channel is coupled to an infrasonic detector for control of a mono/stereo mode switch and a stereo presence indicator. When the received signal is weak, the infrasonic tone is effectively stronger, because the phase angle is increased. Since the s/n ratio is proportional to the phase angle, the stereo presence signal is self-adjusting. The mode switch and indicator are enabled for all values of L and R. The infrasonic tone could also be removed from the transmitted signal whenever the difference signal goes above a predetermined level during stereo broadcasting, in which case a comparator at the receiver would enable the mode switch and indicator upon detection of either a difference signal or the infrasonic tone.

Some Notes On The Calculation of the S/N Ratio For a FM System Employing a Double Sideband AM Multiplex Signal

Equations are developed which determine the S/N ratio for both a monophonic and stereophonic signal including the effect of deemphasis. A S/N ratio loss of 23 Db is indicated.

A Compatible Quadrature System for AM Stereo

The proposal contained herein has been devised to protide a stereophonic broadcasting system which provides a compatible monophonic signal whose spectrum most closely resembles that of the existing monophonic transmission, consistent with the transmission of stereo information, in order to insure the highest degree of compatibility with existing monophonic receivers. In addition the system is designed to provide a minimum of transmitter modification and a stereo receiver of relatively simple design.

An Analysis of the Necessary Decoder Corrections for Color Receiver Operation with Non-Standard Receiver Primaries

A method of color error correction for the Sulphide green and blue phosphors is developed. The method is general in nature and may be used to develop a correction matrix for phosphors with arbitrary color coordinates. A linear matrix is used to obtain an exact coordinate transformation and exact color reproduction within the capabilities of the new phosphors. A non-linear matrix, which gives approximate correction, can be simlated by adjusting the demodulating gains and angles of the color decoder.

A Method of Directly Demodulating Color Signals

Color TV signal evolution is examined from a sampling encoder (modulator) viewpoint. This logically leads to an analysis of decoding (demodulating) the NTSC color signal with sampling techniques. In the process of enumerating and solving the problems that arise by attempting to demodulate by time - interruption of the signal, basic concepts relating to direct demodulation of the NTSC signal are derived.

Application Of Rotationally Non-Symmetrical Electron Lenses to T.V. Image Reproduction

Recent developments in the art have dictated the division of this paper into two component parts. The first deals with a quadrapolar, magnetic lens of rotational non-symmetry used to achieve scan magnification with a television cathode ray tube. The second concerns the development of a negative, electrostatic, gauze lens exhibiting full rotational symmetry which is also used to provide scan magnification.

HDS/NA-6: an analog simulcast high definition television system

A high-definition system for North America (HDS/NA) embracing the simulcast mode of transmission for amplitude-modulated terrestrial and cable environments is described. The AM RF packaging techniques and the pertinent concerns for future tailoring of the system format for taboo channel utilization for broadcast-compatible terrestrial HDTV delivery in 6 MHz are highlighted. Without the constraint of direct NTSC compatibility with this system, carriers may be suppressed and standard NTSC sync headroom may be eliminated. Due to time expansion of all video components, there is a built-in advantage in multipath/echo performance, particularly beneficial for the cable short-echo scenario. The system is naturally expandable to permit an increase in resolution in the presence of additional channel bandwidth. This simulcast format is linked to a linear analog subband subsampling scheme used as a cornerstone for all HDS/NA analog transmission systems, including satellite (FSS and DBS) and augmentation terrestrial and cable formats. The generic HDS/NA subsampling scheme and the packaging of the components for a 6-MHz AM environment are described. >

Simplified Computer-Engineer Interface with the Capability of Complete Design Evaluation

Computers were developed for the primary purpose of solving large scale problems which cannot be simply simulated by analog means, or are related to projects in which design mistakes are intolerable. They were originally applied to problems in the nuclear energy field and to large problems in astrophysics. More recently they have found extensive use in solving repetitive and routine problems which occur in accounting, and presently most large corporations make use of computer equipment designed for this type of problem Computers have been used to a much lesser extent in engineering, mainly because of the difficulty of defining the engineering problems in mathematical terms suitable for routine solution by a computer.

Technical Considerations for Stereophonic Broadcasting on TV

Pertinent parameters of performance and compatibility of stereo sound for Broadcast Television are enumerated. To be of general interest, the treatment begins with FM Phenomena and how it relates to Standard Broadcast FM stereo performance. Subsequently, inter-carrier FM is discussed in full consideration of the complications wrought by stereo. Finally, possible stereo systems for TV sound transmission are briefly described.

History of Usage of Active Devices in Radio a Television Receivers (1962 to Present)

From the earliest days of radio broadcasting, in the early 1920s, the emphasis on vacuum tubes and their associated components was almost entirely dedicated to their use in radio receivers. During World War II the vacuum tube began to take on new roles with the advent of radar, the use of newly developed television techniques for remote control and observation, and the introduction of the vacuum tube as the key element in the first digital computer systems.