Abstract: A memory device requires a minimum of two input/output lines from an external testing device to be coupled thereto. A first DQ line from the memory device provides a direct data path from the array so that the external tester can read data from the array at the maximum speed of the memory device. Test mode circuitry for multiplexing and comparing multiple DQ lines during address compression mode is coupled to two or more DQ lines, including the first DQ line. The compression mode testing circuitry can include on-chip comparators that compare the data simultaneously written to, and read from, the memory device. The comparison circuitry outputs a data test flag indicating whether or not the data read from the memory device matches. The test flag is output through a multiplexer to a second DQ line. As a result, the speed of the device can be tested from the first DQ line, while the results of on-chip comparison can be sampled at the second DQ line.

Abstract: Apparatus for controlling a length of a period during which the output circuitry of a memory array waits before latching the output data including apparatus for detecting the presence of an error in data read from an memory array, apparatus for providing a first value to determine a wait period, apparatus responsive to the detection of an error for providing a second value, apparatus responsive to the first value for generating a signal to latch a data output from the memory array after a first period and responsive to the second value for generating a signal to latch a data output from the memory array after a second period.

Abstract: Digital data is formatted and recorded in track pairs on a tape by the rotary heads of a DAT so as to have a header portion for each track which includes a frame number, error correcting code, ID and so on added to the digital data, the content of each header portion of the tracks for any given frame being equal whereby it is possible to easily detect, upon reproduction, unerased data signals due to head clogging and so on by comparing portions of the two header portions of each frame and error correcting the data from those tracks where it is determined that the compared header portions contain different data.

Abstract: A floppy disk drive apparatus capable of using high- and low-density disks includes an erase section. When it is determined that a floppy disk to be used has a high-density, data is immediately written on the floppy disk in response to a write command. However, when it is determined that the floppy disk to be used has a low-density, data, which has previously been recorded on the recording area of the track where the read/write head is currently located, is erased prior to the writing of new data. After erasure is completed, the new data is recorded on the recording area, in response to a write signal.

Abstract: Width restoring to eliminate unintended width variations in pulse width modulated data in combination with a phase lock loop allows pulse width modulated data in high density optical recordings. The width restoration is accomplished by detecting the timing relationship of the leading and trailing edges of pulses relative to expected timing for the leading and trailing edges. Expected time is derived from a phase locked loop or the original write signal. The detected timing is compared to the expected timing and the timing of the leading and trailing edge signals is corrected. Either analog or digital width correction techniques are used. Width restoration may be used while reading data or while writing the data.

Abstract: A flexible resilient magnetic particle type information card capable of correctly reading information thereon after such card has been bent double on itself and creased, said card comprising a flexible base, a layer of uniformly distributed magnetic particles thereon, and a flexible overlayer of nonmagnetic material, said over layer having a thickness of at least 2 mils, said layer of magnetic particles being magnetically encoded, the magnetic flux transitions of such encoding being at least 0.02 inch apart and said magnetic particle layer being enclosed between the base layer and over layer and spaced from the edges of the card.A method of storing information in binary data form comprising magnetically recording information on a magnetic strip that has an over layer of at least 2 mils by inducing transitions in the magnetization of the strip at a minimum spacing of 0.02 - 0.1 inch.

Abstract: Apparatus in an automatic telephone answering device utilizing a single motor for scanning a tone arm across a grooveless recording disc to selectively play back a message magnetically recorded thereon in a spiral path as well as for rotating the turntable. The apparatus includes an electromagnetic clutch powered by a positive belt drive coupled to the motor for driving a spirally contoured cam to transport the tone arm across the disc. A control circuit including an optoelectronic switch positioned adjacent the edge of the turntable to receive light reflected from a reflective spot on the turntable edge is also provided to initiate scanning by the tone arm coincident with the reflective spot passing by the optoelectronic switch. This insures that the tone arm transducer will begin scanning at the same point for each subsequent playback and/or record operation and, as a result, track the spiral recording path on the grooveless disc.

Abstract: An electronic reminder system is described for recording a plurality of different spoken messages on a record medium, which messages are to be played-back at a specific point-of-time for each message. The system comprises a microphone for recording the spoken messages, a keyboard for inputting data representing the specified point-of-time at which the respective spoken message is to be play-back, a real-time clock for measuring time in a real-time manner and for producing an output corresponding to such real-time measurement, control means controlled by the clock for signaling automatically the arrival of each specified point-of-time at which a recorded spoken message is to be played back, and a speaker for effecting the play-back of the spoken message.