Define stub. Explain single and double stub in brief with neat sketch.

Define stub. Explain single and double stub in brief with neat sketch.
by

1 Answer

Answer :

Stub:- Stub is the piece of short circuited transmission line which is used to tune out the reactance of the load when connected across the transmission line as close as possible

Single stub:- Stub is the piece of short circuited TL which is used to tune out the reactance of the load when connected across the TL as close as possible.

image

The most important feature of single stub matching is that the stub should be located as near to the load as possible. The characteristic admittance of the stub so connected in shunt should be same as that of the main line. The main element of this transmission line is a short circuited section of line whose open end is connected to the main line at a particular distance from the load end. Where the input conductance at that point is equal to the characteristic conductance of the line, and the stub length is adjusted to provide a susceptance equal in value but opposite in sign, to the input susceptance of the main line at that point. So the total susceptance of the main line at that point is zero.  The combination of stub and the line will thus present a conductance which is equal to the characteristic impedance of the line, i.e. the main length of the HF transmission line will be matched


Double stub:- The disadvantages of single stub matching are overcome by using double stub matching as shown in fig.

image

Here, two short circuited stubs at two fixed point usually λ/4 apart are utilized. Their positions are fixed but lengths are independently adjustable. The double stub matching provides wide range of impedance matching. 

by

Related questions

State the need of stub. Explain single stub and double stub matching.

Description : State the need of stub. Explain single stub and double stub matching.

Last Answer : Stub:- Stub is the piece of short circuited transmission line which is used to tune out the reactance of the load when connected across the transmission line as close as possible. ... but lengths are independently adjustable. The double stub matching provides wide range of impedance matching.  

Differentiate between single stub and double stub

Description : Differentiate between single stub and double stub

Last Answer : Differentiate between single stub and double stub

What is stub? What do you mean by single stub matching.

Description : What is stub? What do you mean by single stub matching.

Last Answer : Stub is a piece of short circuited transmission line which is used to tune out the reactance of the load when connected across the transmission line as close as possible. Single Stub Matching : ... The single stub match is perhaps the most widely used matching circuit and can match any load.  

Explain duct propagation with neat sketch.

Description : Explain duct propagation with neat sketch.

Last Answer : Duct propagation is a special type and used for very high microwave frequencies. New phenomenon which occurs in super-refraction, also known as ducting. As the height above earth increases, ... in the standard atmosphere. The Duct propagation is used for very high frequencies in GHz range.

Explain “BALUN” with neat sketch

Description : Explain “BALUN” with neat sketch

Last Answer : Diagram- Explaination

Explain virtual height with respect to wave propagation with neat sketch.

Description : Explain virtual height with respect to wave propagation with neat sketch.

Last Answer : In ionization layer the incident wave refracts and bends down gradually than sharply.   The incident and refracted rays follow paths that are exactly the same as they would have been if reflection had taken place from a surface located at a greater height called virtual height of this layer. 

Explain isotropic radiator with neat sketch.

Description : Explain isotropic radiator with neat sketch. 

Last Answer : An isotropic radiator is a point source that radiates equally in all the directions. It is a hypothetical antenna used as a reference to describe real antenna. The radiation is represented by a sphere with center coincides with location of isotropic radiator.

Explain ground wave propogation with neat sketch.

Description : Explain ground wave propogation with neat sketch. 

Last Answer : Sketch-   Explanationi) It consists of direct wave which travels near the ground from Transmitter to Receiver. ii) The electromagnetic wave leaves the transmitting antenna & remains close to earth surface ... . The ground wave is the path chosen when frequency in between 30 KHz & 3 MHz 

Explain loop antenna with neat sketch. Draw radiation pattern. State its advantages and applications.

Description : Explain loop antenna with neat sketch. Draw radiation pattern. State its advantages and applications.

Last Answer : Loop antenna:-The single turn coil carrying RF current through it having length less than the wavelength.   Advantages:- 1. highly directive 2. Small size Applications:- 1. For direction finding 2. In portable receivers 3. In navigation 

Describe ionosphere with neat sketch.

Description : Describe ionosphere with neat sketch.

Last Answer : The Ionosphere is the upper portion of the atmosphere. The ultra violet radiation from the sun will ionize the upper layer of the atmosphere. Due to ionization these part of the atmosphere becom3es ... electron density of all layers, due to this F2 layer remains present at night time  

Define and explain the term beam width related to antenna with a sketch.

Description : Define and explain the term beam width related to antenna with a sketch.

Last Answer : Definition: The beam width of an antenna is described as the angles created by comparing the half power point (3dB) on the main radiation lobe to its maximum power point. As an example the beam width ... max voltage at center of lobe (these point are known as half power points.) Sketch-  

Define: (i) Image frequency and (ii) Double spotting

Description : Define: (i) Image frequency and (ii) Double spotting

Last Answer : i)Image frequency:- Image Frequency is defined as the signal frequency plus twice the intermediate frequency. It is denoted as fsi = fs+2fi Where, fs = Signal Frequency fi =intermediate frequency ... It is due to the poor front end selectivity i.e., inadequate image frequency rejection.

Explain with a neat diagram of ratio detector. Why limiter stage is not used before ratio detector.

Description : Explain with a neat diagram of ratio detector. Why limiter stage is not used before ratio detector.

Last Answer : With diode D2 reversed , O is positive with respect to b, so that Vab is a sum voltage rather than the difference it was in the discriminator it is now possible to connect a large capacitor ... of limiter stage due to large capacitor C5 .Hence, limiter stage is not used in ratio detector.  

With the help of neat diagram, explain the working of phase discriminator.

Description : With the help of neat diagram, explain the working of phase discriminator.

Last Answer : Explanation:- This discriminator is also known as the center tuned discriminator or the Foster Seeley discriminator after its inventors. It is possible to obtain the same S- Shape response curve from a circuit in ... fin = fc, fin > fc + Δf and fin<fc- Δf should be given marks

Explain effect of 'm' on AM with neat waveforms.

Description : Explain effect of 'm' on AM with neat waveforms.

Last Answer : i)m< 1  If m < 1 or if the percentage of modulation is less than 100% the this type of modulation is known as under modulation The amplitude of modulating signal less than carrier ... greater amplitude part of its information is lost in the process of modulation which is undesirable.

Explain skip zone and skip distance with neat diagram.

Description : Explain skip zone and skip distance with neat diagram.

Last Answer : Skip distance:-Skip distance is defined as the shortest distance from a transmitter, measured along the surface of earth at which a sky wav of fixed frequency returns back to the earth. Skip zone: skip zone where signal is not detectable

Describe line of sight propagation in brief.

Description : Describe line of sight propagation in brief.

Last Answer : Line of sight propagation or Space wave propagation:-   Explanation:- Space wave propagation of electromagnetic energy includes radiated energy that travels in the lower few miles of Earth's ... waves reflected by Earth's surface as they propagate between the transmit and receive antennas. 

Compare between simplex and full duplex communication on the basis of: 1) Definition 2) Sketch

Description : Compare between simplex and full duplex communication on the basis of: 1) Definition 2) Sketch

Last Answer : Compare between simplex and full duplex communication on the basis of: 1) Definition 2) Sketch

State the need of AGC. List the different types of AGC with neat graph.

Description : State the need of AGC. List the different types of AGC with neat graph.

Last Answer : Need of AGC:- The need or purpose of AGC circuit is to maintain the output voltage level (volume) of radio receiver constant over a wide range of RF input signal level.  AGC also helps to smooth out the rapid ... of AGC:- 1) Simple AGC 2) Delayed AGC Graphical representation of AGC:- 

Define the term baluns and explain where is it used?

Description : Define the term baluns and explain where is it used?

Last Answer : A type of electrical transformer used to connect an unbalanced circuit to a balanced oneORA balun is a type of transformer: it's used to convert an unbalanced signal to a balanced ... :- In audio applications, baluns convert between high-impedance unbalanced and low impedance balanced lines.

Fortransmission-line loadmatchingover a range offrequencies,itisbesttouse a a. balun b. broadband directional coupler c. double stub d. single stub of adjustable position

Description : Fortransmission-line loadmatchingover a range offrequencies,itisbesttouse a a. balun b. broadband directional coupler c. double stub d. single stub of adjustable position

Last Answer : c. double stub

Enlist different types of traffic island and explain any one in brief with neat sketch.

Description : Enlist different types of traffic island and explain any one in brief with neat sketch.

Last Answer : The different types of traffic island are as follow: (1) Rotary or central islands. (2) Channelising or refuse islands. (1) Rotary or central islands: A traffic island constructed in ... each site of road intersection. A few typical designs of Channelising islands are illustrated below:

Draw a neat sketch of ‘Locomotive coupler’ mechanism. Explain its working in brief.

Description : Draw a neat sketch of ‘Locomotive coupler’ mechanism. Explain its working in brief.

Last Answer : Figure: Coupler Rod of Locomotive  (Link AD = Link BC = Crank Link CD = Coupling Rod Link AB = Fixed Link = Frame) Working of Coupler Rod of Locomotive: It is an ... center distance between them. This mechanism is meant for transmitting rotary motion from one wheel to the other wheel.

Define the following terms related to antennas; (i) Antenna resistance (ii) Directivity (iii) Antenna gain (iv) Power density

Description : Define the following terms related to antennas; (i) Antenna resistance (ii) Directivity (iii) Antenna gain (iv) Power density

Last Answer : Antenna Resistance - The resistance of an antenna has two components: 1. Its radiation resistance due to conversion of power into electromagnetic waves 2. The resistance due to actual losses in the ... the transmitter power divided by the surface area of a sphere (4πR2) at that distance.

Define critical frequency w.r. to wave propagation.

Description : Define critical frequency w.r. to wave propagation.

Last Answer : Define critical frequency w.r. to wave propagation.

Define VSWR with refernce to standing waves.

Description : Define VSWR with refernce to standing waves.

Last Answer : Voltage Standing Wave Ratio: The voltage standing wave ratio (VSWR) is the ratio of max voltage to min voltage. VSWR= VMAX /VMIN

Define sensitivity with graph.

Description : Define sensitivity with graph.

Last Answer : Define sensitivity with graph.

Define PAM, PWM, and PPM. Draw waveforms.

Description : Define PAM, PWM, and PPM. Draw waveforms.

Last Answer : Pulse amplitude modulation is defined as a process of varying the amplitude of the carrier pulse in accordance to the modulating signal variations. Pulse width modulation is defined as a ... of varying the position of the carrier pulse, in accordance to the modulating signal variations.

Define the transmission line? Draw it‟s general equivalent circuit.

Description : Define the transmission line? Draw it‟s general equivalent circuit.

Last Answer : Transmission line: A conductor or conductors designed to carry electricity or an electrical signal over large distances with minimum losses and distortion.  Equivalent circuit:

Define: 1)Frequency 2)Bandwidth 3)Wavelength 4)Time period

Description : Define: 1)Frequency 2)Bandwidth 3)Wavelength 4)Time period

Last Answer : Frequency: Frequency is the number of cycles per second. Bandwidth: A range of frequencies within a given band, in particular that used for transmitting a signal. Wavelength: Wavelength can be defined as ... for one complete cycle of vibration to pass a given point.  OR Time period=1/frequency

State the types of electromagnetic polarization? Define any one of it.

Description : State the types of electromagnetic polarization? Define any one of it.

Last Answer : Transverse electromagnetic wave:- The polarization of a plane EM wave is simply the orientation of the electric field vector with respect to the surface (i.e. looking at the horizon) If ... the field strength varies with change in polarization the wave is said to have an elliptical polarization 

Define modulation? State the desirable value of modulation index of AM.

Description : Define modulation? State the desirable value of modulation index of AM.

Last Answer : Modulation: It is the process in which any of these Parameters (Amplitude, Frequency, Phase) of high frequency signal (carrier signal) are varied in accordance with low frequency signal(modulating signal) For an AM, modulation index range is 0 to 1.

Define fading? List the causes.

Description : Define fading? List the causes.

Last Answer : The fluctuation in signal strength at a receiver, which is mainly due to the interference of two waves which left the same source but arrived at the destination by different paths, is known ... , such as irrigation, or from multiple transmission paths, irregular earth surfaces, and varying terrains.

Define electromagnetic wave and polarization.

Description : Define electromagnetic wave and polarization.

Last Answer : Electromagnetic wave:-An electromagnetic wave such as light consists of a coupled oscillating electric field and magnetic field which are always perpendicular; by convention Polarization:-polarization" of electromagnetic waves refers to the direction of the electric field.

Define selectivity and sensitivity of AM Receiver.

Description : Define selectivity and sensitivity of AM Receiver. 

Last Answer : Selectivity:-It needs to accept signals of the wanted frequency and reject other unwanted frequencies. Sensitivity:-The sensitivity of a radio receiver is its ability to amplify weak signals. It is ... the receiver input terminals to give a standard output power, measured at the output terminals. 

Define pre-emphasis. State its need. Draw the circuit of pre-emphasis.

Description : Define pre-emphasis. State its need. Draw the circuit of pre-emphasis.

Last Answer : Definition- The artificial boosting of higher modulating frequencies to reduce the effect of noise is called as pre-emphasis. Need:- The artificial boosting of higher audio modulating ... by increasing the amplitude of modulating signal at higher frequencies. Circuit diagram 

Define pulse modulation. State its types.

Description : Define pulse modulation. State its types. 

Last Answer : Pulse Modulation - consists essentially of sampling analog information signals and then converting those samples into discrete pulses. OR It consists essentially of sampling analog information signals and then converting those ... PAM - PWM - PPM  ii) Digital Pulse Modulation - PCM - DM - ADM 

Define modulation index in FM. What is maximum value of deviation ratio.

Description : Define modulation index in FM. What is maximum value of deviation ratio.

Last Answer : Modulation Index of FM: It is defined as the ratio of Frequency Deviation (δ) to the modulating signal frequency (fm). (OR)  

Define the following terms: (i) Polarization (ii) Antenna gain (iii)Antenna resistance (iv)Directivity

Description : Define the following terms: (i) Polarization (ii) Antenna gain (iii)Antenna resistance (iv)Directivity

Last Answer : i) Polarization:- It is defined as the direction of electric field vector in the EM wave radiated by the transmitting antenna. ii) Antenna Gain:- Antenna gain is defined as the ratio of ... in only one direction in which the radiation is maximum. That is directivity = Max. directive gain

Define the terms: 1) Maximum usable frequency 2) Fading

Description : Define the terms: 1) Maximum usable frequency 2) Fading

Last Answer : 1)Maximum usable frequency:- Maximum usable frequency is defined as the limiting frequency ,when the angle of incidence is other than the normal . OR The highest frequency that can be used for sky ... which left the same source but arrived at the destination by different paths is known as fading.

Define standing wave ratio.

Description : Define standing wave ratio. 

Last Answer : Standing wave ratio is defined as the ratio of maximum voltage (Vmax) to minimum voltage (Vmin). Standing wave ratio is also defined as the ratio of maximum current (Imax) to minimum current (Imin).

Define modulation index in AM and give its formula.

Description : Define modulation index in AM and give its formula.

Last Answer : In AM wave, the modulation index (m) is defined as the ratio of the amplitude of the modulating signal (Vm ) to the amplitude of carrier signal (Vc). m = Vm / Vc

Define: Base band signal with one example.

Description : Define: Base band signal with one example.

Last Answer : The electrical equivalent of the original information signal is known as the Baseband signal. Example:-The information or the input signal to a communication system can be analog i.e., sound, picture or it can be digital e.g. the computer data.

Describe in brief with neat sketch: i) English bond ii) Flemish bond

Description : Describe in brief with neat sketch: i) English bond ii) Flemish bond

Last Answer : English bond : The Bond with alternate courses of headers and stretchers with a closer placed next to quoin header is called as the English Bond. Points Should be Remembered for English bond: 1. A ... . 4. Flemish Bond is slightly economical as a number of brick bats can be used.

Describe in brief with neat sketch: i) Base line ii) Check line

Description : Describe in brief with neat sketch: i) Base line ii) Check line

Last Answer : i) Base line:  Base line is generally the longest line running roughly through the middle of the area. It is laid on a level ground as far as possible. The whole frame work is built upon this line. ... on the opposite side or a line joining some fixed point on any two sides of the triangle. 

Describe in brief with neat sketch construction of tunnel with needle beam method

Description : Describe in brief with neat sketch construction of tunnel with needle beam method

Last Answer : In this method stout timber beam known as needle beam is used which forms the main temporary support during the excavation. Construction steps: (a) First of all a small drift of about 1 1 m is ... . (d) After excavation, the lining is provided to the tunnel section and mucking is done. 

Describe in brief caisson foundation for a bridge with neat sketch

Description : Describe in brief caisson foundation for a bridge with neat sketch

Last Answer : Caisson foundation A caisson foundation also called as pier foundation is a watertight retaining structure used as a bridge pier in the construction of a concrete dam or for the repair of ships. It is ... the ground to some desired depth and then filled with concrete thus forming a foundation.

Describe in brief working of Symons rain gauge with neat labelled sketch.

Description : Describe in brief working of Symons rain gauge with neat labelled sketch.

Last Answer : The most common type of non- recording rain gauges used in our country is the Symon's raingauge'.  Working: A Symons Rain gauge consists of a cylindrical vessel of 127 mm internal diameter with an enlarged ... rim which is then measured by the measuring glass in mm' and tenth of mm'

Draw practical set-up and explain the procedure to measure selectivity of radio receiver.

Description : Draw practical set-up and explain the procedure to measure selectivity of radio receiver.

Last Answer : Procedure to measure selectivity of radio receiver: Throughout the measurement the receiver is kept tuned to desired frequency 950 Khz. Now the generator output frequency is deviated below ... the generator output voltage is adjusted to get a standard 50 miliwatt receiver output power.

Explain the working of amplitude limiter in FM receiver with circuit diagram.

Description : Explain the working of amplitude limiter in FM receiver with circuit diagram.

Last Answer : Amplitude limiter: The function of amplitude limiter is to remove all amplitude variation of FM carrier voltage that may occur due to atmospheric disturbances. Use of amplitude limiter makes the system less noisy  Circuit Diagram: