摘要:
Each section (e.g., 102) of the ring oscillator consists of three two-input NOR gates; one in the feedforward path (108), one in the feedback path (112), and one in the crossover path (110). The center frequency of the oscillator is controlled by enabling and disabling the appropriate gates, such that a single closed loop path is formed. The gates in the feedforward and crossover paths are directly enabled or disabled (to disable, either input is held high) from a control circuit (Fig. 2). The gates in the feedback path, however, are indirectly enabled and disabled. To enable a particular feedback path gate (e.g., 118), either the corresponding crossover gate (116) is disabled, or the corresponding feedforward gate is disabled (114) and the crossover gate (122) in the following section is enabled. The later causes the feedback gate (124) in the following section to be dissbled, thereby removing the remaining sections (106) of the oscillator from the closed loop path. The NOR gates are implemented as a differential amplifier (Fig. 5) having two transistors (610 and 612) in the input leg and one transistor (616) with its base connected to a regulated voltage (Vr) in the opposite leg. The output of the NOR gate is taken from the collectors of the input transistors. The propagation delay of the oscillator signal through the gate is minimal because, to switch the output state of the gate, only the state of one of the input transistors (610 or 612) must be changed. The short propagation delay through the gate permits high frequency operation, as well as the ability to program small incremental steps in the center frequency of the oscillator.
摘要:
Fault tolerant logic circuitry wherein the logic gate circuits employed therein each include an input circuit portion and a push-pull output circuit portion. The push-pull output circuit portion of each of said logic gates employed in said fault tolerant logic circuitry having the characteristic that when an output of a first logic gate circuit is connected to an output of a second logic gate circuit, said connection between the outputs of said first and second logic gate circuits will provide a predetermined logical function.
摘要:
For reducing self-induced switching noise a two terminal non-linear impedance means is connected to the collector of an output transistor (T1) of a driver circuit and the reference potential line. It comprises one or more serially connected diodes, which may be formed by the base-collector junctions of bipolar transistors (TS1, TS2).
摘要:
A current controlled gate performing a NOR function utilizes a pair of transistors (T4, T5) acting as current mirrors that receive a DC bias through a large resistor (R B ). This bias occurs when an input transistor (T1, T2) is positive to insure that one of the current mirror transistors (T4, T5) will saturate when the input transistors (T1, T2) are "off" and the other will be driven into saturation when either of the input transistors (T1, T2) is "on". When all inputs are negative, one of the current mirror transistors (T4, T5) saturates thereby reducing the current to the input transistors (T1, T2) effectively to zero. The saturation results in the collector-base capacitance increasing very rapidly such that the input assumes the characteristics of a common emitter due to the large capacitance existing in the collector of the current mirror transistor (T4, T5). An active push-pull output is produced with a single collector path from input to output.
摘要:
A flexible cable assembly for coupling an electronic apparatus, having a port for receiving personal computer cards in accordance with the PCMCIA standard, to at least one peripheral device, said flex cable assembly comprises a personal computer card connector, in accordance with the PCMCIA standard, for connecting into a corresponding port in the electronic apparatus, and a flexible cable connected to the personal computer card connector. The personal computer card connector also comprises an interface to said at least one peripheral device. In accordance with a further aspect of the invention, the flex cable assembly can also couple a first electronic apparatus, to a second electronic apparatus, each having a port for receiving personal computer cards in accordance with the PCMCIA standard. This flex cable assembly comprises (1) a first PCMCIA card connector for connecting into a corresponding port in either the first or second electronic apparatus; (2) a second PCMCIA card connector for connecting into a corresponding port in either the first or second electronic apparatus; and (3) a flex cable coupled between the first and second personal computer card connectors.
摘要:
Disclosed is an apparatus for switching input port connections to output port connections quickly and dynamically using a new asynchronous approach to resolve contention. The disclosed ALL-NODE (Asynchronous, Low Latency inter-NODE) Switch is self-routing in two cycle times at the same high speed serial rate that data is transferred through the switch. The normal mode of the switch requires absolutely no synchronization amongst any of the input and output ports which interface to the switch. The switch is completely completely void of centrally controlled clocking and any data buffering. Data traverses the switch only encountering three gate delays - on-chip receiver, mux, and off-chip driver. Contention is detected and resolved on chip, and yet the logic implementation is extremely simple and low in gate count, so the switch design is never gate limited. The protocol requires several parallel data lines plus two or three control lines.
摘要:
A voltage controlled oscillator is formed of a plurality of cascaded inverter stages in a ring configuration. Each inverter stage is a grounded emitter circuit having an active pull-stage in order to achieve a short stage delay. The frequency of the ring oscillator is determined by the number of inverter stages, and the gain is selectable by coupling an external control voltage to only certain of the inverters. The VCO may be fabricated on a single integrated circuit along with the other circuits necessary to form a phase locked loop or other frequency generation system.
摘要:
A circuit and method for generating a read complete signal for a high speed densely packaged monolithic memory is disclosed. The memory (34) is designed to utilize and externally generated address valid signal which indicates that the address to the memory is valid. The receipt of the address valid signal sets a set/reset latch (18) and starts the memory (34). The addressed memory cells are sensed. When at least one memory cell has data are its output below a threshold, the data are said to be unstable and the set/reset latch is then conditioned to be reset. When the data sensed by all the sensing circuits (36) are stable, a signal (ADV) is sent to the set/reset latch (18) to cause it to be reset. The resetting of the set/reset latch (18) causes an output thereof ot change state. This state change comprises the read complete signal (RC) which is used to determine the read cycle time of the memory and may also be used in diagnostic tests of the memory.