Sampling.docx

SAMPLING GATES 1. Sampling gates are transmission circuits in which the output is the exact replica of the input during a selected time interval and is zero otherwise. 2. The time interval for the transmission of the signal is selected by an externally impressed signal called the gating signal which is usually rectangular in wave shape. 3. The sampling gates are also called transmission gates or selection circuits. 4. A gate circuit that extracts information from the input waveform only when activated by a selector pulse. 5. 6. 7. 8. 9. 10. 11.

TYPES OF SAMPLING GATES sampling gates may be 1. unidirectional sampling gates 2. bidirectional sampling gates Difference between Logic gate and Sampling Gates: A logic gate is a computer circuit with several inputs but only one output that can be activated by a particular combinations of inputs, a diagram that shows the major gates can be found here.

12. 13. An example would be if you have 2 wires going to an AND gate and only 1 wire has a current (is on, 1) and the other one is 0, then your output would be 0 as you need wire 1 AND wire 2 to have a current, for the output to be 1, on. 14. 15. A sampling gate, on the other hand is a circuit that produces an output only when first activated by a preliminary pulse. So if you have a current going through a wire and through a sampling gate, your output would be 0, unless you program the sampling gate to let the current through. 16. 17. Unidirectional sampling gate: 18. 19. A unidirectional gate can transmit either positive or negative pulses (or signals) to the output. It means that this gate transmits pulses of only one polarity to the output. The signal to be transmitted to the output is the input signal. This input signal is transmitted to the output only when the control signal enables the gate circuit. Therefore, we discuss two types of unidirectional diode gates, namely, unidirectional diode gates that transmit positive pulses and unidirectional diode gates that transmit negative pulses. 20. 21. Bidirectional sampling gate: 22. 23. A bidirectional gate can transmit both positive and negative pulses (or signals) to the output. It means that this gate transmits pulses allow two polarities to the output. The signal to be transmitted to the output is the input signal. This input signal is transmitted to the output only when the control signal enables the gate circuit. Therefore, we discuss two types of bidirectional diode gates bidirectional transistor gates that transmit positive pulses and transmit negative pulses.

24. 25. Applications of sampling gates: 26. 27. Sampling gates find applications in many circuits. Sampling gates are used in multiplexers, D/A converters, chopper stabilized amplifiers, sampling scopes, etc.