Ampex Corporation

Command Audio Corporation

Eric F Morrison

Anthony Edward Zank

A programming system in which entertainment and information programming is transmitted, received and stored in real time by a multitude of receivers. The stored programming subsequently may be retrieved by a user in non-real time at the user's convenience. This programming system is particularly adaptable for use with receivers located in moveable vehicles wherein, however, the mobile receivers must have access to the transmitted information, that is, to a transmitter, regardless of the extent of the vehicle's journey. To this end, one or more transmitters located within respective service areas transmit identical programming information along with respective transmitter location codes over different frequency channels, wherein each code also defines a transmitter priority of effective radiated power. As the vehicle moves within a service area, if a loss of signal occurs, the receiver selects the transmitter with the next highest priority from the transmitter location codes for that and neighboring overlapping service areas. The location codes previously are stored and periodically updated in the receiver memory. The transmitter location code may comprise a two byte word multiplexed with the information signal, wherein the first byte contains the stations or transmitter channel numbers within the respective service areas, and the second byte defines the priority of each transmitter in terms of effective radiating power.

Method and apparatus for transmitter identification and selection for

An entertainment service consists of program material which is encoded, supplied and stored in receivers for later retrieval at the convenience of a subscriber or user. A number of unique options are available and include a format for the presentation of audio/video commercials and other message materials without interfering with the delivery of the program materials within which the message materials are to be inserted. Message materials may be targeted at specific program subscriber groups and specific program categories. The entertainment materials are electronically supplied in a unique format of the program and message materials selectively interspersed with program break flags and message flags. The flags identify and provide preselected access to the materials previously determined by the subscriber's service. The program break flags indicate where message materials are to be inserted in the program material, and the message flags identify the specific message to be inserted as well as provide time related information. The subscriber may select program material at his or her convenience in non-real time from a menu corresponding to the subscribed services.

Method and apparatus for encoding and storing audio/video information

The data rate of speech and non-speech audio is selectively reduced by respective compression techniques based upon the information content of the type of signal. A composite audio information signal formed of speech and non-speech audio is applied to both a voice encoder and a wide-band audio compression encoder. An audio-type detection circuit examines the speech spectrum as well as the entire frequency spectrum and dynamic range of the audio information and generates a selection signal indicating whether the signal is speech or non-speech audio. A composite encoded audio signal is produced by intermingling the outputs of the encoders in response to the selection signal. The composite encoded audio signal and an identification signal indicative of the audio signal type are transmitted to respective receivers at the reduced data rates for storage, and subsequent decoding and retrieval by a listener as an audible signal in response to the transmitted identification signal.

Digital audio data transmission system based on the information content

There is disclosed herein an apparatus and method for accurately ascertaining the time of occurrence of passage of the leading and trailing edges of an input pulse through the 50% amplitude level. The apparatus implements the transfer function 1 - cos(wt) where t is equal to the round trip delay through a delay line, and w is the angular velocity of each fourier component of the input signal. In one embodiment, a summing resistor and a delay line having a characteristic impedance equal to that of the resistor are used. The output of the delay line is coupled to one input of a comparator, and the other input is coupled to the junction between the summing resistor and the delay line. Another embodiment uses two matched delay lines, two factoring circuits, a summing circuit and a comparator to implement the same transfer function.

Synchronization slicer

Non-orthogonality of the blanking region information caused by the 25 Hz offset in a digital PAL-encoded color television signal is corrected by a dynamic offset circuit. To this end, a plurality of waveforms describing the envelopes of the blanking, sync and burst are stored, and during video signal processing are sequentially addressed at a 25 Hz rate. The resulting assembled output blanking information is orthogonal to the television scanning frequency.

Blanking signal generator for a subcarrier locked digital PAL signal

A gray scale test chart for television cameras, in the form of either a transmittance chart or reflectance chart, includes one or more regions having selected gray values for calibrating or adjusting the output signal of the television camera, each gray value region being formed by an array of uniformly black dots arranged on a uniformly white background in a spatial frequency selected with respect to the resolution capability of the camera to produce an integrated output signal while being within the resolution capability of a photographic or other chart reproduction technique, the size of the dots in each region determining its gray value in combination with the spatial frequency or center-to-center spacing of the dots.

Reproducible gray scale test chart for television cameras

Apparatus is disclosed for providing error compensation of a video information signal having a format. Sampling of the analog PAL format video information signal is done at a rate of four times the chrominance subcarrier frequency and is done in a precise manner whereby the samples are taken along orthogonal vector axes that are oriented at 45.degree. relative to the U and V vector axis. When samples are taken at the prescribed locations, substitute samples in the form of multi-bit digital words can be used as replacements for defective or missing sample words, which replacement samples exhibit the same vector phase as the defective sample, but which are taken from either the preceding or succeeding line relative to the line in which the defective sample is located. The apparatus of the present invention obviates the necessity of performing any arithmetic computation to derive the value for the sample to be substituted. Moreover, the sample is spatially closely related to the defective sample, i.e., it is merely spatially removed one horizontal line from the line of interest and is vertically aligned relative to the defective sample. The detection of a defective sample activates the apparatus to automatically substitute the proper digital data word sample for the defective sample. If part of or an entire line is missing or defective, the system automatically inserts an average of the preceding and succeeding line during the period of time when the missing or defective information is detected.

Apparatus for providing dropout compensation and error concealment in a

A digital chrominance signal in a digital component television system is digitally filtered to obtain sampling values intermediate the sampled values obtained during analog to digital conversion of the chrominance signal, such that the resultant number of chrominance samples per second in the digitized chrominance signal corresponds with the number of luminance samples per second in the digitized luminance signal. The samples values of the digitized chrominance signal including the computed intermediate values may also be modified by said digitized filter to minimize the alias created by the analog to digital correction sampling process, to compensate this signal for sine x/x losses existing in the digitized chrominance signal, to compensate for Gaussian filter attenuation of the chrominance signal prior to analog to digital conversion thereof, and to compensate for other deficiencies in the chrominance signal. The digital filter includes a network of at least one shift register and one digital adder that continuously calculates intermediate values between successive sample values of a digital chrominance signal, and incorporates said calculated values in a resultant chrominance signal.

Digital chrominance filter for digital component television system

A wideband chroma key switching signal is generated from lower bandwidth chrominance signals in a video signal by first conventionally generating a chroma key switching signal from these chrominance signals, and then detecting high frequency transition components in the corresponding luminance signal. These luminance signal high frequency components are then added to the switching signal in a manner that insures that their polarities match, thereby generating a higher bandwidth chroma key switching signal. This resultant higher bandwidth chroma key switching signal is used to control cross fade amplifiers which function to output either the video signals of a first or a second scene with linear transitions between these video signals during switching.

Chroma key switching signal generator

A total raster error measurement and correction circuitry, using digital memory means in the camera head for the storage of correction data, corrects spatial scan, shading, etc., errors in a television picture in two dimensions. The basic spatial error correction circuit effectively synthesizes horizontal rate waveforms on a number of discrete lines of the vertical scan. On all scanned lines between discrete lines, a linear approximation between the two discrete waveforms is made to form a vertically continuous waveform. Black and white shading errors are measured by comparing the black and white video levels against respective selected black and white D.C. levels with and without a cap on the camera lens. Gamma correction is provided by comparing the peak black and white levels to derive any gray level errors. The total raster error correction data are retrieved from memory and are applied to given image pickup sensors and corresponding video processing circuits in the camera head system during real time operation.

Total raster error correction apparatus and method for the automatic set

An aperture correction system employing a tapped delay line includes an integral detection/gating circuit, whereby the combination generates an improved video detail signal by removing the objectionable noise and low amplitude components which are emphasized during the aperture correction process, while retaining the original shape of the high frequency video detail transitions as enhanced by the aperture correction process. The objectionable noise cancellation is provided by selectively gating the aperture correction signal via the detection/gating circuit in response to a selected gating waveform provided from the video detail signal itself. The detection/gating circuit may be selectively disabled to cause severe attenuation of the waveform at selected low and high frequencies outside the passband of the system.

Growing community of inventors

Redwood City, CA, United States of America

Eric F Morrison