410 results about "Fall time" patented technology

Binary and Quadrature Feher's Modulation (F-Modulation, or FMOD) Transmitter-Receiver systems and circuits exhibit reduced envelope fluctuation and peak radiation, and increased efficiency. A subclass of these systems has a constant envelope. They advantageously provide lower power operation with improved performance including robust BER performance, and compatibility with both linearly and nonlinearly amplified narrow spectrum, and without disadvantages of conventional BPSK, DBPSK QPSK and pi/4-QPSK. Feher's BPSK (FBPSK) is an improved efficiency transmitter which is compatible with conventional BPSK receivers. FBPSK modems are based on using quadrature structure where Q-channel data is inserted in quadrature with I-channel data for certain applications. The Q-channel data may be “offset” from the I-channel data by an amount selectable between zero and a specified time. Further improvement in the spectrum is attained using correlation between I and Q channels. FBPSK modem is shown to meet the IEEE 802.11 specified spectral direct sequence spread spectrum mask (−30 dB point) for wireless LAN, and leads to an output power gain of 6.5 dB over conventional BPSK modems. The cross-coupled quadrature FMOD structure is also suitable for continuous mode and for burst operated TDMA, FDMA, CDMA, WCDMA and CSMA Frequency Modulation Quadrature AM (QAM), QPSK and offset QPSK, as well as pi/4-shifted QPSK modems/processors. Reduced modulation index Gaussian FSK (GFSK), multilevel FM and cross-coupled Quadrature Amplitude Modulated (QAM) transmitters and combinations of these modulations and corresponding coherent demodulators are disclosed. Controlled rise and fall time descriptions of burst operated systems are included.

Line load compensation and reflection reduction in a signal transmitting circuit is provided using feedback capacitors. The feedback capacitor serially coupled with a resistance generates an RC rise/fall time that is independent of the line load. Additionally, by selecting a capacitor that yields a rise/fall time of approximately ⅓ of the maximum bit transmission time, signal reflection on the signal line can be reduced. Accordingly, by incorporating the feedback capacitor with a differential drive circuit, such as the IB 485 driver, variations in line load can be compensated for while also reducing signal reflection due to un-terminated or improperly terminated signal lines, thus allowing a free topology implementation.

There is provided method for transmitting binary data contained in respective successive time cells, the data being in the form of an optical signal obtained by amplitude modulation and frequency modulation of an optical carrier wave, with a 0 bit data value having a 0 bit mean amplitude having a 0 bit amplitude time duration and a 0 bit frequency having a 0 bit frequency duration, and a 1 bit data value having a 1 bit mean amplitude having a 1 bit amplitude time duration and a 1 bit frequency having a 1 bit frequency duration; the improvement wherein: independently adjusting the 0 bit mean amplitude relative to the 1 bit mean amplitude; independently adjusting the 0 bit frequency relative to the 1 bit frequency; and independently adjusting time duration of the frequency profile of the 1 bit relative to the time duration of the amplitude profile of the 1 bit, whereby to extend the error-free propagation of the optical signal though a dispersive optical fiber beyond the dispersion limit. There is provided a method for transmitting Non-Return-To-Zero (NRZ) binary data contained in respective successive time cells, the data being in the form of an optical signal obtained by amplitude modulation and frequency modulation of an optical carrier wave, with a 0 bit data value having a 0 bit mean amplitude having a 0 bit amplitude time duration and a 0 bit frequency having a 0 bit frequency duration, and a 1 bit data value having a 1 bit mean amplitude having a 1 bit amplitude time duration and a 1 bit frequency having a 1 bit frequency duration; the improvement wherein: the phase across each 1 bit data value is substantially constant, and the phase of the carrier changes across each and every 0 bit by an amount equal to the product of the frequency difference between the 1 bit and the 0 bit and the duration of the 0 bit; whereby to extend the error-free propagation of the optical signal though a dispersive optical fiber beyond the dispersion limit. In accordance with one form of the present invention, there is provided a method for transmitting binary data contained in respective successive time cells, the data being in the form of an optical signal obtained by amplitude modulation and frequency modulation of an optical carrier wave, with a 0 bit data value having a 0 bit mean amplitude having a 0 bit amplitude time duration and a 0 bit frequency having a 0 bit frequency duration, and a 1 bit data value having a 1 bit mean amplitude having a 1 bit amplitude time duration and a 1 bit frequency having a 1 bit frequency duration; the improvement wherein: the amplitude profile of the 1 bit is substantially bell-shaped, and the frequency profile of the 1 bit is substantially square-shaped, with steeper rise and fall time and a wider flat top region; whereby to extend the error-free propagation of the optical signal though a dispersive optical fiber beyond the dispersion limit.

An optical disk recording method includes the steps of: providing a multi-pulse chain from a recording wave; independently changing the pulse rise timing and pulse fall timing (pulse width) of the first pulse in the multi-pulse chain in accordance with a preceding space length and a recording mark length; changing the pulse rise timing and pulse fall timing (pulse width) in accordance with a following space length and the recording mark length in a predetermined timing or in independence; and in relation to the smallest mark recorded by irradiation with mono pulse, changing the rise timing in accordance with the preceding space length and the recording mark length and the fall timing (pulse width) in accordance with the following space length and recording mark length, compensating various optical disks different in recording material without change of the fundamental waveform.

An apparatus and method for applying pulsed electromagnetic therapy to humans and animals. A straight wire element is employed to generate the magnetic field. A power and timer circuit supplies current pulses that approximate square pulses in form, so that the straight wire element generates magnetic pulses having rapid rise and fall times. Peak field strength is approximately 2 gauss at a 1 cm distance from the straight wire element, and the duration of peak field strength is approximately 200 nanoseconds. The pulses are repeated at a frequency of about 70 Hz. The straight wire element and circuit may be housed in a hand-held probe, with an LED illuminating the skin area to provide a visual indication of effective range, or a plurality of the straight wire elements and associated circuits may be embedded in a conformable pad that is placed over the affected area of the body.

An external transmitter circuit drives an implantable neural stimulator having an implanted coil from a primary coil driven by a power amplifier. For efficient power consumption, the transmitter output circuit (which includes the primary coil driven by the power amplifier inductively coupled with the implanted coil) operates as a tuned resonant circuit. When operating as a tuned resonant circuit, it is difficult to modulate the carrier signal with data having sharp rise and fall times without using a high power modulation amplifier. Sharp rise and fall times are needed in order to ensure reliable data transmission. To overcome this difficulty, the present invention includes an output switch that selectively inserts a resistor in the transmitter output coil circuit in order to de-tune the resonant circuit only during those times when data modulation is needed. Such de-tuning allows sharp rise and fall times in the data modulation without the need for using a high power modulation amplifier. Because data modulation is typically needed for only a small percent of the time that a carrier signal is present, it is thus possible using the present invention to achieve reliable data modulation, transmission and reception without having to use a high power modulation amplifier in the transmitter.

The apparatus for partial discharge detection of turn-to-turn insulation in motor has a surge generator for generating a surge voltage to the windings of the motor by applying a pulse voltage, and a partial discharge current detector for detecting partial discharge currents between the winding turns of the motor. The surge generator generates in and between the windings of the motor the surge voltage that has the rise time and fall time corresponding to the rise time of the surge voltage observed at the motor terminal when the motor is driven by an inverter, and that is repeated at a frequency of 50 Hz to 20 kHz.

A phase-based TOF system preferably generates an optical waveform with fast rise and fall times, to enhance modulation contrast, notwithstanding there will be many high order harmonics. The system is preferably operated with an odd number of phases, to reduce system bias error due to the higher order harmonics, while maintaining good modulation contrast, without unduly increasing system memory requirements. Preferably the system can dynamically calibrate (and compensate for) higher order harmonics in the TOF generated optical energy waveform, over time and temperature. Within the optical energy transmission channel, or within the optical energy detection channel, detection amplifier gain may be modified, and/or detector signal integration time may be varied, and/or digital values may be employed to implement calibration and error reduction The resultant TOF system can operate with improved phase-vs-distance characteristics, with reduced calibration requirements.

A voltage level shifting circuit (10) transitions an input signal at a first voltage to a second voltage higher than the first voltage. A cross-coupled latch provides the second voltage. Cascode configured transistors (16, 26) are connected in series with input transistors (18, 28) that receive the first voltage in complementary form. Capacitive devices (34, 40) are connected between the first voltage and gates of the cascode configured transistors for allowing independent small signal variations to occur on the gates of the cascode configured transistors for better control of duty cycle and rise and fall time matching of the level shifting circuit. Isolation devices (32, 38) permit independent modification of small signal voltages to occur on the gates of the cascode configured transistors.

The present invention contemplates a variety of improved techniques for the fast switching of current through, among others, LED loads. A current shunting device is utilized to divert current away from a load at high speed when activated, thus enabling the control of the amount current that flows through the load.

The present invention provides an array of pixels for the detection of a flash of electromagnetic radiation or a cloud of impinging high energy particles. Each pixel in the array comprises a radiation receptor for converting the electromagnetic radiation or impinging high energy particles into a radiation signal, and a converter for converting the radiation signal into pulses. The array further comprises a circuit for comparing one or more of the criteria pulse amplitude, pulse arrival time, time to convert a pulse in a digital signal, pulse duration time, pulse rise and fall time or integral of pulse over time for pulses coinciding on pixels in a predetermined neighborhood. The array also comprises a circuit for suppressing those pulses that are compared negatively versus the corresponding pulses in another pixel of the neighborhood for the same one or more criteria. A corresponding method is also provided.

Improvements in and relating to electronic pulse generation or oscillation circuitry based on a signal path exhibiting endless electromagnetic continuity and affording signal phase inversion in setting pulse duration or half-cycles of oscillation within time of signal traverse of said signal path, and having active switching means associated with said signal path to set rise and fall times of each said pulse or said half-cycle of oscillation, including for frequency adjustment by selective inductance and power saving without stopping pulse generation or oscillation.

To provide a hot stand-by switching apparatus which is cheaper and more reliable than a conventional RF power switching device. Further, Output level and frequencies during rise and fall times are stabilized. The hot stand-by apparatus of the present invention comprises coupler for outputting either the active signal or the preparative signal, active and preparative transmitters, and switches which are connected with the input terminals of transmitters, respectively.

The invention discloses a voltage phase angle jumping detection method at the falling time of network voltages, comprising the following steps of: obtaining, by sampling, three-phase network voltages VA(k), VB(k) and VC(k); detecting a voltage angle [gamma] (k) of synchronous rotation of the network voltages at the sampling time; converting the three-phase network voltages into Vd(k), Vq(k) weights under a d-q synchronous rotation coordinates system; taking the Vd(k), Vq(k) weights under the current d-q coordinates system and Vd(k-1), Vq(k-1) weights at the last sampling time as known quantities, and calculating to obtain an amplitude |V1(k)| of a current positive-sequence weight and a sine and cosine value thereof with a d axis included angle [theta]1(k); directly using an amplitude |V2(k)| of a negative-sequence weight and the sine and cosine value thereof with a d axis included angle [theta]2(k) for the control and calculation subsequent to the falling malfunction of the voltage; or implementing an inverse trigonometric operation on the sine and cosine values of the[theta]1(k) and the[theta]2(k) according to practical requirements so as to obtain voltage positive/negative-sequence phase angle variable quantities [delta][phi]+ and [delta][phi]- that occur on account of the falling of the voltage.

A process inserts a random noise in a Time to Digital Converter (TDC) designed for calculating the phase error between a first high frequency signal F_DCO with respect to a second reference signal, switching at a lower frequency. The process involves: processing of the first signal F_DCO by using a chain of delays having a set of n elementary delays which number is chosen so as to extend over a full period of the first signal; storing the outputs of the chain of delays in a set of latches and generation of a thermometer code presenting a stream of “1” separated from a stream of “0” by a border corresponding to the transition of the first signal with respect to the second reference signal; reducing the thermometer code by a random number PN of bits; processing of the result in an edge detecting and thermometer code decoding so as to generate two variables Δt_r and Δt_f which are representative of the difference between the rise and fall time of the first signal with respect to the second reference signal; computing the normalized gain so as to generate an average value of 1/T_DCO; adding to the value Δt_r a binary value corresponding to the number of bits PN; multiplying the preceding result by the average value of 1/T_DCO and computing the phase error between the signals. The delay chain may be arranged with inverters. The process is particularly but not exclusively useful for carrying out a TDC convertor for the purpose of synthesizing of frequencies.

The invention relates to a liquid crystal display driving device. The liquid crystal display driving device comprises a scan driving unit, a data driving unit, a grid line, a data line and a pixel region which is formed by the grid line and the data line, wherein the grid line comprises a grid scanning line and a redundant grid line; the data line comprises a data signal wire and a redundant data line; and the liquid crystal display driving device also comprises a compensating circuit which is connected with the grid line for compensating a grid scanning signal on the grid scanning line to improve voltage delay phenomenon on the grid scanning line. The liquid crystal display driving device provided by the invention can compensate the grid scanning signal through the compensating circuit which is connected with the grid line, so that the influence of overtime of resistance-capacitance (RC) on the rise time and/or the fall time of the grid scanning signal can be reduced, the charging time requirement of a pixel can be fully met, and the charging rate of the pixel is ensured.

A ramp voltage generating apparatus according to the present invention includes a ramp voltage generating circuit for generating a plurality of ramp voltages out of phase with each other from one ramp voltage, and a control circuit. The ramp voltage generating circuit includes a plurality of voltage generating circuit portions connected in parallel to a voltage input terminal. Each voltage generating circuit portion includes a voltage output terminal, a capacitor, an operational amplifier, a first switch, a second switch and a third switch. The control circuit turns on the third switches while shifting the time point of switching each of the third switches from off to on state, and the control circuit turns off the first switches and, also, turns on the second switches during the period including the fall time point of the ramp voltage input to the voltage input terminal.

A level shifting circuit can include a shift stage that latches first and second internal nodes to opposite shifted logic potentials in response to different transitions at an input signal node. The input signal node can vary between non-shifted logic potentials. An output stage can enable a first controllable impedance path coupled between an output node and a first shifted power supply node in response to a first type transition at the first internal node, and can enable a second controllable impedance path coupled between the output node and a second shifted power supply node in response to the first type transition at the second internal node.

The embodiment of the invention provides a shift register unit, a gate drive circuit and a display device, and can enhance the output capacity of a signal output end and shorten the fall time of output waveform. The shift register unit provided by the invention comprises a first output module, a second output module, an input module, a drop-down control module, a drop-down module and a reset module, wherein under the control of a pull-up control node, the signal of a clock signal end is output to a signal output end; under the signal control of a signal input end, the voltage of a first power supply end is output to the pull-up control node; under the signal control of the signal input end, the signal of a drop-down control node drops down to the voltage of a second power supply end; under the control of the drop-down control node, the signals of the pull-up control node and the signal output end drop down to the voltage of the second power supply end; under the control of a reset signal end, the signal of the first power supply end is output to the drop-down control node. The shift register unit, the gate drive circuit and the display device, provided by the embodiment of the invention, are applied to the production and manufacturing of display panels.

Unit circuits 11 each including a TFT T2 (output transistor), a TFT T1 (input transistor), and a TFT T8 (output reset transistor) are cascade-connected, and a gate terminal of the TFT T8 is connected to a gate terminal of the TFT T2 included in a next stage unit circuit 11. By applying a post-boot potential that is higher than an ON potential of the TFT T8 to the gate terminal of the TFT T8, driving capability of the TFT T8 is increased. Accordingly, it is possible to reduce falling time duration of the output signal Q and a layout area of the TFT T8. In this manner, a shift register with a small area capable of resetting an output signal at high speed is provided.