Que4.5. Explain modification process.
Answer 1. Modification is a process which increases( amplifies) the signal for enjoying or digitization.
2. Signal amplifiers frequently include electronic factors that amplify signals without producing significant quantities of thermal noise.
3. In some operations a signal must be amplified or downgraded in order to drive a circuit or a system.
Que4.6. What are the colorful types of amplifiers?
Answer There are numerous types of amplifiers used in signal exertion including the following
1. Voltage amplifiers They’ve a concinnity gain, so the affair signal is a reduplication of the input signal. This type of amplifier is substantially used as an impedance matching device.
2. insulation amplifiers These are designed specifically to insulate high DC situations from the data accession device while passing the fairly small AC or discrimination signal. The inputs and labors are electrically insulated.
3. Instrumentation amplifiers These are discriminational amplifiers that have been optimized for use with DC signals. They’re characterized by high gain, high Common Mode Rejection rate( CMRR), and high input impedance.
4. Sample- and- hold amplifiers These amplifiers indurate the analog voltage incontinently. During this process the HOLD command is issued and analog voltage is available for an extended period.
5. Current amplifier As the name suggests, an amplifier that makes the given input current advanced. It’s characterized by a low input impedance and high affair impedance.
6. Voltage amplifier An amplifier that amplifies given voltage for a larger voltage affair. It’s characterized by a high input impedance and low affair impedance.
7. Transconductance amplifier An amplifier that changes affair current according to changing input voltage.
8. Transresistance amplifier An amplifier that changes affair voltage according to changing input current. It’s also known as a current- tovoltage motor.
9. functional amplifiers( Op- Amps)
i. An op- amp is an intertwined circuit that acts as a voltage amplifier, and has discriminational input.
ii. It has a positive and negative input, but a single affair with veritably high gain. Firstly, op- amps were created using faucets.
10. stopcock( or) vacuum tube amplifiers
i. An amplifier that uses vacuum tubes to give an increased power or voltage affair is known as a stopcock( or) vacuum tube amplifier.
ii. Op- amps were firstly of the stopcock type, but were replaced by ICs formerly they got cheaper, in lower operations at least.
iii. In high power operations, they ’re still in use because of their cost effectiveness and affair quality. They’re used in radar, service, high power radio and UHF transmitter operations.
11. Transistor amplifiers
i. A transistor amplifier is amulti-configuration high affair amplifier that uses transistors as the working base.
ii. These include Bipolar Junction Transistors( BJTs) and Metal Oxide Semiconductor Field- Effect Transistors( MOSFETs).
i. A special type of direct ray vacuum tube, used as an amplifier in high radio frequentness.
ii. It’s largely precise and used in large scale operations, generally comes under microwave oven amplifiers.
13. Instrument amplifiers Especially designed amplifiers to amplify sound, voice or music. Used substantially in musical instrument operations.
14. Distributed amplifiers Amplifiers that use transmission lines to temporarily resolve the input and amplify each member collectively are called distributed amplifiers. They ’re generally set up in oscilloscopes.
Que4.7. bandy functional amplifiers in detail with suitable illustration.
Answer functional amplifiers
1. utmost data accession systems use a number of different types of circuits to amplify the signal before processing.
2. ultramodern analog circuits intended for these data accession systems comprise introductory integrated functional amplifiers, which are configured fluently to amplify or cushion signals.
3. Integrated functional amplifiers contain numerous circuit factors, but are generally portrayed on schematic plates as a simple logical functional block.
4. A many external resistors and capacitors determine how they serve in the system.
5. Their extreme versatility makes them the universal analog structure block for signal exertion.
6. utmost functional amplifier stages are called flipping ornon-inverting as shown.
7. A simple equation relating to each configuration provides the idealized circuit earnings as a function of the input and feedback resistors and capacitors.
8. Also, special cases of each configuration make up the rest of the abecedarian structure blocks, videlicet the concinnity- gain follower and the difference amplifier.
Flipping amplifier stages
1. The inverter stage is the utmost introductory functional amplifier configuration.
2. It simply accepts an input signal substantiated to common, amplifies it, and inverts the opposition at the affair outstations.
3. The open- circle gain of a typical functional amplifier is in the hundreds of thousands.
4. But the idealized amplifier used to decide the transfer function assumes a gain of perpetuity to simplify its derivate without introducing significant crimes in calculating the stage gain.
5. With such a high stage gain, the input voltage sees only the voltage separator composed of Rf and Ri.
6. The negative sign in the transfer function indicates that the affair signal is the inverse opposition of the input.
7. Without inferring the transfer function, the affair is calculated from, Vo = – Vin( Rf/ Ri) where, Vo = Affair signal,( V) Vin = Input signal,( V) Rf = Feedback resistor,() Ri = Input resistor,() Non-inverting amplifier stages
1. Thenon-inverting amplifier is analogous to the former circuit but the phase of the affair signal matches the input.
2. Also, the gain equation simply depends on the voltage separator composed of Rf and Ri.
Que4.8. Explain discriminational amplifiers.
Answer 1. Differential- input amplifiers offer some advantages over flipping and non-inverting amplifiers.
2. It appears as a combination of the flipping andnon-inverting amplifiers as shown.
3. The input signal is impressed between the functional amplifier’s positive and negative input outstations and can be insulated from common or a ground leg.
4. The voluntary ground leg is the key to the amplifier’s inflexibility. The affair signal of the discriminational input amplifier responds only to the discriminational voltage that exists between the two input outstations.
5. The transfer function for this amplifier, Vo = ( Rf/ Ri)( V1 – V2) 6. The major benefit of the discriminational amplifier is its capability to reject any voltages that are common to both inputs while amplifying the difference voltage.
7. The voltages that are common to both inputs are meetly called common mode voltages( Vcm or CMV).
8. The common- mode voltage rejection quality can be demonstrated by connecting the two inputs together and to a voltage source substantiated to base.
9. Although a voltage is present at both inputs, the discriminational amplifier responds only to the difference, which in this case is zero.
10. The ideal functional amplifier, also, yields zero affair volts under this arrangement.
Que4.9. bandy programmable- gain amplifiers in detail with suitable illustration.
Answer 1. Programmable gain amplifiers are generallynon-inverting functional amplifiers with a digitally controlled analog switch connected to several resistors in its feedback circle.
2. An external computer or another sense or double signal controls the nontransferable inputs of the analog switch so it selects a certain resistor for particular gain as shown.
3. The data accession system’s signal conditioners smell the input signal breadth and automatically shoot the proper double law to the Programmable Gain Amplifier( PGA) to increase the gain for a low signal, or drop the gain for a large signal.
4. The input signal also can be measured and displayed without deformation.