When the switch is opened, the capacitor holds the voltage level until the next sampling time. When the switch is closed, the capacitor charges to the D/A converter output voltage.
The disadvantage here is that the analog output signal must be held between sampling periods and the outputs must therefore be equipped with sample hold circuits.Ī sample hold amplifier can be approximated by a capacitor and high gain opamp, as shown in Fig. This is called multiplexing, and is shown in Fig. The second method involves using only one D/A converter and switching its output.The proper converter is then selected for decoding by the select lines. The digital input lines are connected in parallel to each converter. This has the advantage that each signal to be decoded is held in its register and the analog output voltage is then held fixed. The first method, is to simply use a D/A converter for each signal, as shown in Fig.There are two methods of decoding these signals. Quite often it is necessary to decode more than one signal, e.g. Hence data are entered into the register each time the read in (strobe) pulse occurs. When the read line goes high, one of the two gates connected to the F/F is true (enabled) and the F/F sets or resets accordingly. Each F/F is a simple RS type F/F and requires a + ve level at R or S inputs to The F/F on the right represents the MSB and the F/F on the left LSB. and 1Gbps Parallel-to-Serial MII Converter General Description The MAX24288 is a flexible, low-cost IEEE 1588 clock and timestamper with an SGMII or 1000BASE-X serial interface and a parallel MII interface that can be configured for GMII, RGMII, or 10/100 MII. The amplifier works in such a way that when the input from an F/F is high, the output of the amplifier is at +10, and when the input from the F/F is low, the output is 0 V.įour F/Fs used form the register necessary for storing the digital information. One input is the +10 V from the precision voltage source, and the other is from an F/F. The level amplifiers have two input each. The resistive network used is of the ladder type. 17.20, and a complete block diagram of a 4-bit DA Converter Working Principle is shown in Fig. A basic block diagram of a D/A converter is shown in Fig. (DAC), serial-to-parallel converter, discrete Fourier. Additionally, it contains transmit and receive amplifiers and isolators. Finally there must be some form of gating on the input of the register, such that the F/F’s can be set with the proper information from the digital system. A block diagram of a gated, stepped-frequency GPR RF system is shown in Figure 3.13, and includes the RF source, the quadraphase modulator, the receive mixer, filters, the IF amplifier, and the demodulator. There must also be a level amplifier between the register and the resistive network, to ensure that the digital signals presented to the network are all of the same levels and are constant. The simplest register is formed using an RS flip-flop, with one F/F per bit.
An integral part of a D/A converter is a register which can be used to store digital information.
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