Que4.10. What’s data accession? Give its factors.
Data accession( DAQ)
1. Data accession( DAQ) is the process of measuring an electrical or physical miracle similar as voltage, current, temperature, pressure, vibration or sound with a computer.
2. A DAQ system consists of detectors, DAQ dimension tackle, and a computer with operation software.
1. Detector A detector, also called a transducer, converts a physical miracle like temperature or vibration, into a measurable electrical signal like voltage or resistance.
2. DAQ device A DAQ device acts as the interface between a computer and signals from the outside world by digitizing incoming analog signals to be computer readable. DAQ bias include three crucial factors Signal conditioning circuitry Transforms noisy real- world signals into forms that can be effectively and directly measured.
Analog- to- digital transformers( ADCs) Digitize real- world analog data into digital representations that can be manipulated by computers. Computer machine Enables the DAQ device to transmit data to a computer. exemplifications include USB, PCIe, or Ethernet.
3. Computer and software A computer with DAQ software is needed to reuse, fantasize, and store dimension data. motorist software Gives operation software the capability to control your DAQ device with menu- grounded configuration or a programmable API.
operation software Gives the stoner a ready- made experience for acquiring, assaying, and presenting data. Configuration is done using menu- grounded interfaces.
Programming terrain Allows druggies to develop their own operation to acquire, dissect, and present data, using libraries of functions( APIs) to pierce and control their DAQ device.
Que4.11. Explain analog to digital motor.
Answer 1. Analog to Digital Converter( ADC) is an electronic intertwined circuit used to convert the analog signals similar as voltages to digital or double form conforming of 1s and 0s.
2. utmost of the ADCs take a voltage input as 0 to 10 V, – 5 V to 5 V,etc., and similarly produces digital affair as some kind of a double number.
3. Analog to digital motor samples the analog signal on each falling or rising edge of sample timepiece. 4.11.1. ADC motor. Vdd Analog ADC double affair signal input
4. In each cycle, the ADC gets of the analog signal, measures and converts it into a digital value.
5. The ADC converts the affair data into a series of digital values by approximates the signal with fixed perfection.
6. In ADCs, two factors determine the delicacy of the digital value that captures the original analog signal. These are quantization position or bit rate and slice rate as shown.
7. Bit rate decides the resolution of digitized affair and you can observe as.
2 where 3- bit ADC is used for converting analog signal.
9. Assume that one volt signal has to be converted from digital by using 3- bit ADC. 10. thus, a aggregate of 23 = 8 divisions are available for producing 1 V affair. This results1/8 = 0.125 V is called as minimal change or quantization position represented for each division as 000 for 0 V, 001 for , and likewise upto 111 for 1V. 4.11.2. Analog to digital conversion process. Ideal transfer characteristic Analog signal n- bit digital word Analog input signal 8/8 Full scale Digital affair bn b2 b1 b0 111 110 101 100 011 010 001 000 b2b1b0 ADC
11. still, 8, 12, If we increase the bit rates like 6., we will get a better perfection of the signal.
12. therefore, bit rate or quantization gives the lowest affair change in the analog signal value that affect from a change in the digital representation.
Que4.12. bandy the different types of analog to digital motor.
Answer Types of analog to digital transformers Dual Slope A/ D Converter 1. In this type of ADC motor comparison voltage is generated by using an integrator circuit which is formed by a resistor, capacitor and functional amplifier combination.
2. By the set value of Vref, this integrator generates a sawtooth waveform on its affair from zero to the value Vref.
3. When the integrator waveform is started similarly athwart starts counting from 0 to 2n – 1, where n is the number of bits of ADC.
4. When the input voltage Vin equal to the voltage of the waveform, also control circuit captures the counter value which is the digital value of corresponding analog input value.
5. This binary pitch ADC is fairly medium cost and slow speed device. timepiece Control sense Counter in bits) CLK CLR CLK affair buffer – – D7 D6 D5 D4 D3 D2 D1 D0 Vin – Vref 4.12.1. Binary pitch A/ D motor. Flash A/ D motor
1. This ADC motor IC is also called as resemblant ADC, which is a most extensively used effective ADC in terms of its speed.
2. This flash analog to digital motor circuit consists of a series of comparators where each one compares the input signal with a unique reference voltage.
3. At each comparator, the affair will be high state when the analog input voltage exceeds the reference voltage.
4. This affair is further given to precedence encoder for generating double law grounded on advanced order input exertion by ignoring other active inputs. This flash type is a high- cost and high- speed device. ? ? ? ? Input analog voltage Reference voltage V1.0 V V R R R R V V 4.12.2. Flash A/ D motor.
Successive approximation A/ D motor
1. The SAR ADC is a ultramodern ADC IC and important faster than binary pitch and flash ADCs since it uses a digital sense that converges the analog input voltage to the closest value.
2. This circuit consists of a comparator, affair latches, consecutive approximation register( SAR) and D/ A motor. Control sense consecutive approximation register Digital to analogue motor Comparator Analogue input – 4.12.3. Consecutive approximation A/ D motor.
3. At the launch, SAR is reset and as the LOW to HIGH transition is introduced, the MSB of the SAR is set.
4. also this affair is given to the D/ A motor that produces an analog fellow of the MSB, further it’s compared with the analog input Vin.
5. still, also MSB will be cleared by the SAR, If comparator affair isLOW.otherwise the MSB will be set to the coming position.
6. This process continues till all the bits are tried and after Q0, the SAR makes the resemblant affair lines to contain valid data.
Que4.13. Give the operations of ADC.
Answer 1. They’re used in computer to convert the analog signal to digital signal.
2. They’re used in cell phones.
3. They’re used in microcontrollers.
4. They’re used in digital signal processing.
5. They’re used in digital storehouse oscilloscopes.
6. They’re used in scientific instruments.
7. They’re used in music reduplication technologyetc.
Que4.14. Explain Digital to Analog Converter( DAC).
Answer 1. Digital to Analog Converter( DAC) is a device that transforms digital data into an analog signal.
2. According to the Nyquist- Shannon slice theorem, any tried data can be reconstructed impeccably with bandwidth and Nyquist criteria.
3. A DAC can reconstruct tried data into an analog signal with perfection.
4. The digital data may be produced from a microprocessor, operation Specific Integrated Circuit( ASIC), or Field Programmable Gate Array ( FPGA), but eventually the data requires the conversion to an analog signal in order to interact with the real world.
Que4.15. bandy the different types of Digital to Analog Converter DAC).
Answer There are two styles generally used for digital to analog conversion R- 2R graduation network system
1. The R- 2R graduation DAC constructed as a double- weighted DAC that uses a repeating protruded structure of resistor values R and 2R.
2. This improves the perfection due to the relative ease of producing equal valued-betrothed resistors( or current sources).
3.Fig.4.15.1 shows the 4- bit R- 2R graduation DAC. In order to achieve highlevel delicacy, we’ve chosen the resistor values as R and 2R.
4. Let the double value b3b2b1b0, if b3 = 1, b2 = b1 = b0 = 0, also the simplified form ofFig.4.15.1 DAC circuit is shown inFig.4.15.2. The affair voltage is V0 = 3R( i3/ 2) = Vref/ 2.
5. also, If b2 = 1, and b3 = b1 = b0 = 0, also the affair voltage is V0 = 3R( i2/ 4) = Vref/ 4 and the simplified circuit is shown inFig.4.15.3.
6. still, also the simplified form of Fig, If b1 = 1 and b2 = b3 = b0 = 0.4.15.3 DAC circuit is shown inFig.4.15.4. The affair voltage is V0 = 3R( i1/ 8) = Vref/ 8.
7. Eventually, the circuit is shown inFig.4.15.5 corresponding to the case where b0 = 1 and b2 = b3 = b1 = 0. The affair voltage is V0 = 3R( i0/ 16) = Vref/
16. Weighted resistors system
1. The introductory operation of DAC is the capability to add inputs that will eventually correspond to the benefactions of the colorful bits of the digital input.
2. In the voltage sphere, that’s if the input signals are voltages, the addition of the double bits can be achieved using the flipping summing amplifier as shown.
3. In the voltage sphere, that’s if the input signals are voltages, the addition of the double bits can be achieved using the flipping summing amplifier.
4. The input resistors of the op- amp have their resistance values ladened in a double format.
5. When the entering double 1 the switch connects the resistor to the reference voltage.
6. When the sense circuit receives double 0, the switch connects the resistor to base. All the digital input bits are contemporaneously applied to the DAC.
7. The DAC generates analog affair voltage corresponding to the given digital data signal.
8. For the DAC the given digital voltage is b3, b2, b1, b0 where each bit is a double value( 0 or 1). The affair voltage produced at affair side is, V0 = R0/ R( b3 b2/ 2 b1/ 4 b0/ 8) Vref
9. As the number of bits is adding in the digital input voltage, the range of the resistor values becomes large and consequently, the delicacy becomes poor.