Tandy Corporation

Other

Paul T Schreiber

Douglas R Curtis

Jerry J Heep

A system relating to improved coin currency containment, collection, and retrieval, when carrying or utilizing a purse or pocketbook. The system provides an exterior-mounted coin slot that directs loose coin from such coin slot into an interior expandable zippered pocket within the pocketbook. Alternately, the pocket has a window to view such stored coin in the internal coin pocket portion, assisting a user in easy recognition and retrieval of desired coin from the pocket. It may, under appropriate circumstances, also be used on other personal item carriers such as, purses, handbags, wallets, backpacks, messenger bags, attach&#xe9;s, fanny packs, duffel bags, luggage, etc.

Coin convenience systems

An intelligent power switching system for controlling the electrical connection of a power source to each of a plurality of outputs, such as personal computer components or electronic entertainment equipment. Switch circuitry is coupled to relay circuitry for generating signals responsive to user commands to select an 'on' or 'off' state with respect to each output. A processor receives switching signals and generates control signals to effect actuation of the relays. Responsive to user programming commands, the processor stores the switching signals, their sequence and the time delay between their generation. Responsive to a subsequent abbreviated user 'power-on' command, the processor generates control signals by reading the stored switching signals, their sequence and time delay, and automatically actuates the relays with respect to each output in the same order and with the same time delay as defined by the user programming commands. A 'power off' command causes the relays to be actuated in the reverse order.

Intelligent power switcher

An automatic transistor checking method is provided, whereby an unknown, bipolar transistor may be typed, pinned and checked for forward DC gain, H.sub.fe. The method is suitable for portable instruments, because the method uses little battery current to perform the H.sub.fe measurement. The method automatically determines transistor type (NPN or PNP) and pinout, making it suitable for quick checking of batches of unknown devices.

Automatic transistor checker

A relatively large protection resistor is connected between the measurement in-out terminal and the internal circuitry of a digital multimeter. A clamping circuit at the input to the internal circuitry insures that any voltage applied to the input terminal will be dropped across the protection resistor, thereby avoiding an over-voltage condition which could damage the internal circuitry. A resistive divider network used to make measurements is connected between the protection resistor and the clamping circuit and is designed to take the protection resistor into account during measurements.

Single string resistive divider network for a digital multimeter

A high resolution video graphics system for use with a processor and characterized by improved memory expandability particularly in connection with color display. The high resolution video graphics system includes a video memory which is preferably comprised of a plurality of video memory planes and video counter means for providing display timing. There are basically four buses that are used with the system including a control bus, a read bus, a write bus, and an address bus. A multiplexer means is provided for receiving either video counter addresses or direct addresses from the processor. There is associated with the video memory means for converting to serial output data which the preferred embodiment includes a series of shift registers corresponding to the number of separate memory planes employed. In the preferred embodiment the system has three memory planes, each of 16K by 16 capacity. The shift register output is coupled to a high speed static palette RAM with the shift register outputs being the addresses thereto. The data outputs of the palette RAM couple to guns on a color monitor or to the back plane in connection with black and white graphics.

High resolution video graphics system

A bandpass filter suitable for use in modem circuitry and other applications which require the filter's center frequency to be switched is disclosed. The filter circuit has the characteristic that although the center frequency is changed the overall gain of the filter remains constant. This characteristic results from using a plurality of filter sections which each have low individual gain and providing compensating gain at the input of the filter. In addition, compensating gain elements are used in each filter section so that when the center frequency of the filter is changed, the gain of each filter stage remains constant.

Switchable bandpass filter

Electronic circuitry for generation of graphics images on a computer display screen is disclosed which allows graphics capability to be added or retrofitted to computers having standard video display character generation circuitry. The graphics circuitry receives address, data and control signals from the normal computer peripheral bus. Address signals received by the graphics circuitry are interpreted as command signals and, in accordance with the command signals, data present on the computer peripheral data bus is interpreted either as graphics data to be written in a random access graphics memory or as an address location for such data in the memory. The graphics circuitry normally operates asynchronously with respect to the computer under control of the character clock generated by the character generation circuitry. Proper synchronization with computer operation is achieved by using wait commands which cause the computer circuitry to cease processing temporarily while write or read operations are being processed by the graphics circuitry. In addition, special circuitry is provided which allows the graphics circuitry to automatically increment and decrement address information stored within the circuitry.

Computer graphics generator

An interface circuit is disclosed for connecting a digital computer to a modem or other peripheral circuit through either a standard digital signal (RS232) 'port' or an audio-frequency 'port' normally used by the computer to store and retrieve information on audio-frequency magnetic tapes. The interface circuit allows the modem to be used economically with a small computer which does not have a standard RS232 'port'. In order to allow the modem to connect to the audio-frequency 'port' the interface circuitry combines filtered audio signals received by the modem from an associated telephone line with RS232 signals generated by the modem decoding circuitry to produce tone bursts which can be decoded by the computer audio-frequency port. The interface circuitry can accept either RS232 signals or tone bursts from the computer to be transmitted by the modem by automatically adjusting an internal threshold level.

Growing community of inventors

Fort Worth, TX, United States of America

Paul T Schreiber