Abstract: A single electronic device is disclosed that splits a transport stream in order to simultaneously produce NTSC and ATSC standard outputs with the same video and audio content so that the same content can be viewed side-by-side on a standard definition NTSC television and an ATSC digital HDTV set at the same time.

Abstract: A high definition television player records and plays back HDTV signals in a closed circuit to demonstrate high definition television. The signals are recorded on a hard drive, CD, DVD or the like in discrete 2-meg data blocks, with each block of data being separately identified. The invention provides for continuous looping play of a desired program or programs by identifying the starting data block and ending data block of the program. The program play is begun at the starting block. When the program is finished at the end block, play continues at the start block, and so on until the stop button is pushed.

Abstract: An 8-VSB modulated signal is produced using software to randomize, encode and interleave an MPEG II data signal and then converting the 2-bit encoded signals to 3-bit encoded signals using hardware.

Abstract: A method and apparatus are disclosed for capturing and storing digital high definition television signals. The signals are taken from an input device in 8-bit parallel fashion at a constant flow rate and put into each of four 8-bit first in-first out memory registers until they are half full. After the respective first in-first out memory registers are half filled, additional quantities of data equal to half filling the registers are added while the data from the first half register filling is presented to the system memory as 32 bit words. That data is filled into a first of two concurrent blocks of system memory and after the first block is filled, while the second block is filled, the data is written from the first of the two concurrent blocks into another part of the system memory. The transfer of the 32-bit data words is accomplished at a faster rate than the input rate of the 8-bit data.

Abstract: A method and apparatus are disclosed for generating an 8-level vestigial side band modulated radio frequency signal as a high definition television test signal. The invention utilizes the above in connection with a single ISA bus computer board that may be utilized in a personal computer for generating signals used to demonstrate HDTV products without the need for over the air HDTV broadcast signals.

Abstract: A test apparatus and method of testing a capacitor while it is still in-circuit incorporation a sequence of tests including a DC capacitance value measurement, a measurement of the DC current paths in parallel with the capacitor, a measurement of the equivalent series resistance of the capacitor, and an AC impedance measurement of the capacitor and its associated circuitry.

Abstract: An insulative caliper type pivotal mounting pivotally secures two elongate arms that at their free ends mount a pair of electrically conductive pointed contacts. Electrical conductors connected to the contacts extend through each of the insulative elongate arms and through the elastic pivotal mounting from which they exit as a coaxial cable. On the distal end of the coaxial cable is positioned a quick connect-disconnect jack adapted for mounting onto a complementary jack in an electronic test instrument. The separation between the pointed ends of the contacts is infinitely adjustable by means of a thumb screw having reversed threaded studs extending from the opposed sides of the center thereof into threaded pivotal mountings on each of the elongate arms. The dual point test probe may be infinitely adjusted, maintained in the predetermined separation and may be manually manipulatable by the single hand of a user when testing current, voltage drop, capacitance, inductance or the like between the contact points.

Abstract: A method and apparatus for testing the horizontal drive stage of a cathode ray tube display where the horizontal drive stage has a drive output which is directed to the base of a horizontal output transistor. In the method and apparatus, the output from the horizontal drive circuit is disconnected from the base of the horizontal output transistor and is connected to the apparatus of the present invention. The apparatus includes a load which simulates the load normally provided by the base of the horizontal output transistor. A meter differential amplifier is connected across the load and readings therefrom are projected on a display. The horizontal drive stage is then energized and readings from the display are compared to known operating requirements of the base of the horizontal output transistor.

Abstract: A method and apparatus for testing flyback transformers counts the number of cycles of a decaying ringing signal generated in a resonant circuit including the secondary winding of the flyback transformer beginning with the second cycle and ending with the cycle where the amplitude of the ringing signal falls below twenty-five percent of the amplitude of the second cycle of the ringing signal.

Abstract: A method and apparatus provides sweep control signals for an expanded display of a selected portion of a television signal. A first counter is preloaded with a number related to the position of the left hand edge of the selected portion of the waveform being monitored and a second counter is preloaded with a number related to the position of the right hand edge of the selected portion of the waveform. Clock pulses are counted by the first counter until the number preloaded therein is reached and then the second counter counts the clock pulses until the number preloaded therein is reached. Control signals are developed when each of the counters has counted the number preloaded therein.

Abstract: The horizontal output stage of a television receiver is tested by denergizing the receiver so as to remove B+ voltage from the horizontal output stage, and then powering the horizontal output stage from an independent low voltage DC power supply through a switch which is turned on and off at the horizontal sweep frequency to permit making measurements of operating parameters of said horizontal output stage.

Abstract: A train of constant current pulses is applied to a capacitor to raise the voltage across the capacitor from a first predetermined level to a second predetermined level. The voltage across the capacitor is measured only during the intervals between the current pulses, and the number of applied pulses is counted and used to calculate the capacitance of the capacitor.

Abstract: An FM stereo generator for use as a modulator or in a test instrument or the like to provide the conventional 19 KHz and 38 KHz signals. The phase of the generated 19 KHz pilot subcarrier signal is fixed relative to the 38 KHz carrier signal. The 38 KHz double sideband suppressed carrier signal is generated in a digital synthesis circuit to provide a stable 38 KHz carrier signal. The left and right stereophonic audio signals are applied to operational amplifiers to provide sum and difference audio components. The difference component is applied as an input to a double sideband suppressed carrier digital-to-analog converter which is responsive to the synthesis circuit to provide the 38 KHZ carrier signal. The 19 KHz pilot subcarrier signal is generated by a digital-to-analog converter that is clocked by a crystal timer which is common to both signals thereby to lock the phase of the pilot signal to the 38 KHz signal.

Abstract: An instrument for measuring the equivalent series resistance of a capacitor includes a plurality of constant current generators across which a capacitor under test is adapted to be connected. A selected one of the generators is periodically enabled to supply a constant current to the capacitor and the voltage across the capacitor is measured and displayed a short time after the generator is enabled, after which time the capacitor is discharged and the measuring cycle is repeated.

Abstract: A composite RF television signal is converted to an IF signal, passed through an AGC circuit and the amplitudes of the horizontal sync pulses are sampled only during the horizontal sync period. The high and low peak samples are stored and the difference between the levels of these peak samples, which is proportional to the HUM in the system, drives a meter calibrated to show the percent of HUM in the composite RF television signals.

Abstract: An instrument for testing the multichannel sound circuits of a television receiver provides a plurality of discrete test signals respectively consisting of a carrier sine wave modulated with an audio frequency sine wave having an amplitude and phase which matches the MTS encoding formula.

Abstract: The signal-to-noise ratio of the video portion of a television signal is measured by measuring the noise level in a 200 KHz band spaced 2 MHz from the video carrier during the vertical sync period and the carrier level is also measured during the vertical sync period. The two measurement signals are sequentially applied to a microprocessor which calculates the signal-to-noise ratio from the two measurements and drives a meter which displays the signal-to-noise ratio in decibels.

Abstract: A frequency counter employs a temperature sensitive oscillator mounted in proximity to a master crystal oscillator to provide an output frequency which varies appreciably with changes in ambient temperature and the frequency of the temperature sensitive oscillator is periodically counted and compared to a table of correction factors stored in memory to select a correction factor which is applied to the counted frequency of an input signal to provide a temperature corrected frequency count.

Abstract: The sweep trigger pulses generated internally in an oscilloscope are coupled to a pulse counter, which counter is reset periodically and a number proportional to the count accumulated during each period is displayed.

Abstract: Tracking of the electron guns of a multiple-gun cathode ray tube system is tested by individually testing the emission current of each gun, storing voltages proportional to the emission currents of each gun and subsequently selecting the highest voltage stored and comparing it to each of the stored voltages.