[introduction] pass in the digital data that passes cable in be defeated, often use pass date to invert alternately (AMI) encode, because this is planted,encode did not shed weight continuously. Besides, the bandwidth of AMI signal also should be compared equivalent clear (RZ) yard is small. Below normal circumstance, to produce such as AMI such ambipolar weaveform, need is used losing two power source.

Pass in the digital data that passes cable in be defeated, often use pass date to invert alternately (AMI) encode, because this is planted,encode did not shed weight continuously. Besides, the bandwidth of AMI signal also should be compared equivalent clear (RZ) yard is small. Below normal circumstance, to produce such as AMI such ambipolar weaveform, need is used losing two power source. Additional, ambipolar weaveform produces circuit to may want to use imitate cell. However, this design example cancelled all these requirements, use an a few the door, trigger and individual 5V power source to be able to input generation AMI weaveform from NRZ only.

Referenced graph 1, NRZ signal (graph 2a) and clock use AND1 to door choosing is connected and produce RZ weaveform together (graph 2b) . This RZ signal is received repeatedly subsequently as scale down implement end of D trigger clock. The Q that catchs RZ signal and trigger and / Q output undertakes choosing connecting together, two on-line that carry AND2 and NAND door output are handed in change pulse comes apart. NAND door is used on the 2nd line in order to obtain in opposition undee (graph 2c) .

Graph 1: NRZ uses only power source to produce ambipolar pulse to AMI converter.

Because the delay time of NAND wants to be more than AND door, because this outputs end use AND4 in AND3,undertake compensating (the logistic series parts of an apparatus that can use according to place changes) . The output drive of AND4 and NAND door 75 Ω resistor, output end to increase tension effectively in the door then. If two output are tall n, the voltage of resistor joint is tall n. If among them an output end is low, another is tall, the voltage of resistor joint is half tall n. When two output is carried is low n when, the electric crimp of joint is bordering on 0V. Such, the weaveform that nods in R1 and R2 join had what make the same score around dc to losing pulse. This signal is passed after lying between straight capacitance C1, can get in output end dc n is the truly ambipolar weaveform of 0 (graph 2d) .

Graph 2: Undee: (A)NRZ input; (B)AND4 output; (C)NAND output; (D)AMI output

Graph the 2 weaveform that showed emulation circuit. Emulator can catch what appear in door output end very small aiguille, nevertheless these aiguille won’t produce a problem in be used actually. The NRZ signal rate that produces is 2.048Mb/s. Because use, is TTL parts of an apparatus and 5V power source, because n of signal of this summit summit is less than ± 2.5V. If need taller range, can use the CMOS parts of an apparatus that has taller logistic amplitude.

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