Clock pulse

Like the Wein-bridge oscillator, the Schmitt trigger only needs a power supply of 5 to 15V to begin its oscillation. This entails that the maximum lead that the clock pulse can drive is in the 1 mA range. The oscillation is controlled by the RC time constant and the hysteretic native to the Schmitt trigger. 

Clock Pulse D/A Converter Input D/A Converter Output (Fdac Volts) Comparator Output (Kcomp Volts) Bit Value... 

Fig. 6.75. Parallel-to-serial conversion of digital signals (t, - time elapsed after initial clock pulse)...

The imaging array 10 defines a number of rows 16 of CCD bits. Each column of bits in the array is in essence a vertical CCD shift register, where data can be shifted from one bit to the adjacent bit by application of clock pulses from a clock generator. Alternate rows 16 are characterized as optically active, the remaining interlaced rows (such as row 16a) are characterized as optically inactive. The CCD bits in the optically inactive rows are covered by opaque strips. Radiation generated minority carriers are collected alternately from a scene and... 

In a shift register, a selection pulse is shifted from one stage to the next at every clock pulse. The frame rate and the number of rows in the display determine the requirements for the clock frequency. As the image update time of the display is 600 ms, a frame rate of approximately 10 Hz is sufficient for black and white images. This enables e-reading applications. The corresponding minimum clock fre-... 

Fig. 14.16. Measurement results of the 32-stage shift register. The top graph shows the clock pulses and the start pulse the bottom graph shows the output pulse of the 32nd stage after 0, 2, and 4 h respectively.

Figure 8 shows the input and output waveforms for 100-kHz operation of a 10-/an-pitch device. Clock pulses were 20- 30 V. Seven continuous pulses... 

UART Acronym for Universal Asynchronous Receiver/Transmitter. An electronic module that combines the transmitting and receiving circuitry needed for asynchronous transmission over a serial line. Asynchronous transmissions use start and stop bits encoded in the data stream to coordinate communications rather than the clock pulse found in synchronous transmissions. 

Fig. 7 shows the block diagram 112-bit PRSR. This shift register includes 112 stages divided into three chunks of 16, 32 and 64 stages together with 6 switches S0-S5. It employs more robust counter-flow design , e.g. the stream of data and clock pulses flow in opposite directions. By applying DC current to different combination of the switches... 

Scanning The sequencer synchronises the recording with the action of an external scanner. The sequencer delivers two additional dimensions, X and Y. Synchronisation with the scanner is obtained by sending to or receiving clock pulses from the scanner. The result is a spatial array of data sets, each of which can be multidimensional, due to the capabilities of the channel control. 

Fig. 3.10 Image acquisition by synchronising the recording with an external scanner. Data acquisition is s)mchronised with the scanning via the frame clock, line clock, and pixel clock pulses. For each detector, a stack of images for consecutive times in the laser pulse sequence is built up...

In both cases the data acquisition in the TCSPC channels is synchronised with the scanning by clock pulses from the scan controller. It must, however, be taken into account that the length of the lines of the scan varies since the return points of the scan are controlled by the detector overload signals. Therefore, the scan software must store the positions of the return points and the number of pixels between. These positions are used later to adjust the lines horizontally. 

A data latch can be built using JK flip-flops, clocked flip-flops, and all varieties of synchronous master-slave flip-flops (see Figure 23.17B). The clocked flip-flop data-latch operates in much the same way as the RS flip-flop data-latch the TP line must undergo a negative-going 1 to 0 transition each time data is transferred. However, the clocked flip-flop data-latch will operate only in a synchronous manner (that is, each time a negative-going clock pulse is present), in contrast to the RS flip-flop data-latch, in which the outputs will follow the inputs whenever the TP input is 0. 

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