6 – Delta-Sigma Digital to Analog Converter How does Digital to Analog Converter (DAC) Work
The output from DAC is filtered out to produce Analog signal.įig. Each bit of the sample is converted serially. 1-Bit DACĭigital samples are converted back into Analog form for further amplification. It converts data into high speed bit-stream. Delta-Sigma Modulatorĭelta-Sigma Modulator acts as a High-Pass Filter to the quantization noise and Low-Pass Filter to the signal. The data from the Filter is the input to the Modulator block. It increases the sample rate and reduces the time and thus, sampling frequency is increased by four times. Analog Output Filter Interpolation Filter.6 shows Delta-Sigma DAC which consists of different blocks namely: It is the fastest and highest precision DAC. The size of the encoder grows exponentially with the increase in input bits, and more switches and interconnection is required. This is done to shrink the size of the chip. Thermometer-coding is used for MSB and Binary-weighted structure is applied for LSB.
How an bnc analog to digital video converter code#
The input binary code is separated into 2 segments. Binary Weighted and Thermometer-coded DAC are combined.
In such cases no architecture is ideal and hence two or more DAC’s are combined and designed. Segmented DAC’s are designed according to the specifications based on performance. 4 – Binary Ladder or R–2R Ladder Converter Circuit Segmented DAC Hence the output voltage of R–2R Ladder DAC is given by the equation:įig. Now, adding the Op-amp to the circuit, V 4 becomes the input to the non-inverting Amplifier whose Gain is defined by the equation: Similarly, with the change in the input bits, the voltage will be V/4, V/2, V/16…… etc. Now the output for the reduced network is given by. To understand its working, let us consider only the Resistors in the network, omitting Op-amp and assuming the input to be DCBA = 1000.
It is the simplest type of DAC where the switch between ground and inverting input of the Op-amp is controlled by the input bit.įig.4 shows Binary Ladder or R–2R Ladder DAC. The conversion speed reduces in this type of DAC due to parasitic capacitance. This type of Converter has only two values of Resistors, R and 2R. 3 – Binary Weighted Resistor Circuit Binary Ladder or R–2R Ladder D/A Converter Circuit The output voltage is obtained by substituting different values of inputs in the equation as shown in the table below:įig. and V is the output Analog Voltage. The output of the Summing Amplifier circuit is given by the equation: Here, A, B, C, D are the digital inputs where ‘D’ is at MSB and ‘A’ is at LSB. These Resistors at the input terminal are called as Variable Resistors. 3 below shows a typical Binary Weighted Resistor Converter Circuit which consists of an Op-Amp, four resistors which are connected at the input terminal of Op-amp along with the Feedback Resistor. The output is generated through this Summing Amplifier Circuit. These resistors are connected across the inputs and the summing point. In this type of Converter, every digital input bit that needs to be converted, requires one resistor or current source. Delta-Sigma DAC Binary Weighted Resistor D/A Converter Circuit.Binary ladder or R–2R ladder D/A Converter Circuit.Binary Weighted Resistor D/A Converter Circuit.There are basically four types of Digital to Analog Converter circuits namely: 2 – Block Diagram of Digital to Analog Converter (DAC) Types of Digital to Analog Converter (DAC) The digital inputs are d 0, d 1, d n-2, d n-1 and V a is the output Analog Voltage.įig. Analog signal is necessary to drive Motors, temperature controller etc.įig.2 shows a block diagram of DAC circuit which shows n-bit digital inputs converted to Analog Signal. This digital signal is converted back to Analog signal for further processing i.e.
In any communication system, the analog signal which is in the form of physical variables is converted to digital value by ADC. 1 – Introduction to Digital to Analog Converter What is Digital to Analog Converter (DAC)ĭigital to Analog Converter (DAC) basically converts digital code that represents digital value to analog current or voltage.įig. This post will discuss in detail about what is Digital to Analog Converter (DAC), it’s types, how it works, applications, advantages and disadvantages. Digital to Analog Converter (DAC) is an integrated circuit that converts digital signal to analog voltage/current which is necessary for further Analog Signal Processing.
0 kommentar(er)
