# State and explain the concept of transmission bandwidth.

State and explain the concept of transmission bandwidth.

Bandwidth is defined as the portion of the electromagnetic spectrum occupied by a signal  We may also define the bandwidth as the frequency range over which as information signal is transmitted.  Bandwidth is the difference between the upper and lower frequency limits of the signal.  We already know different types of baseband signals such as voice signal, music signal, t.v signal etc. Each of these signals will have it’s own frequency range. This frequency range of a signal is knows as it’s bandwidth.  For example the range of music signal is 20 HZ to 15 KHZ. Therefore the bandwidth is(f2-f1)  BW= f2 - f1= 15000-20=14980Hz

## Related questions

Description : State and explain concept of bandwidth.

Answer : 1. Bandwidth is defined as a range within a band of frequencies or wavelengths. ... For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second. For analog devices, the bandwidth ... or Hertz (Hz) 2.Suppose the frequency range is f1 to f2 , then B.W= f2 - f1

Description : State the IF frequency and bandwidth of FM receiver.

Description : State and explain the losses in transmission line.

Answer : Losses in Transmission Line:- There are three ways in which energy, applied to a transmission may desperate before reaching the load. They are 1) Radiation Losses:- Its occurs when a ... down voltage of the dielectric insulator. Generally when corona occurs, the transmission line is destroyed.

Description : Explain pre-emphasis and de-emphasis concept in FM.

Answer : Pre-emphasis:- In an FM system the higher frequencies contribute more to the noise than the lower frequencies. Because of this all FM systems adopt a system of pre-emphasis where the higher frequencies are ... at receiver to improve the noise immunity Pre-emphasis/ De-emphasis graph:

Description : Compare PAM, PWM, and PPM on the basis of i. Variable characteristics ii. Bandwidth iii. Information contained in iv. Transmitted power

Answer : Compare PAM, PWM, and PPM on the basis of i. Variable characteristics ii. Bandwidth iii. Information contained in iv. Transmitted power

Description : Show that AM wave consist of two side bands and carrier. Also prove the bandwidth of AM is double of the modulating frequency.

Description : Differentiate between AM and FM on the basis of: (i) Definition (ii) Bandwidth (iii) Modulation Index (iv) Application

Answer : Compare AM and FM on the basis of i)Definition ii)Bandwidth iii) Wave propogation iv)Number of sidebands

Description : For AM, fc =500kHz , fm = 5 kHz Determine: (i) Upper and lower sideband frequencies (ii) Bandwidth

Answer : Given data fc = 500KHz , fm = 5KHz USB =fc+fm USB = 500+5  =505 KHz. LSB =fc – fm LSB = 500 – 5  =495 KHz Bandwidth = 2fm .  = 2* 5 =10 KHz

Description : In a FM system, the maximum deviation is 75KHz. Find bandwidth for modulating frequency i. fm=500Hz ii. fm=5KHz iii. fm=10KHz Draw conclusion for bandwidth of FM from answer.

Answer : Given deviation∆=75kHz i) fm=500Hz bandwidth B.W=2(∆+fm)  =2(75k+500)=151kHz  ii). fm=5KHz bandwidth B.W=2(∆+fm)  =2(75k+5k)=160KHz iii) fm=10KHz bandwidth B.W=2(∆+fm)  =2(75k+10k)=170KHz As the modulating frequency increases bandwidth also increases.

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

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

Description : Calculate the characteristics impedance for a transmission line having L=0.5 mH/Km, C=0.08 µF and negligible R and G.

Answer : L=0.5 mH/Km C=0.08 µF

Description : a) For a transmission line, Find SWR and reflection coefficient R if, i. There is no reflected voltage. ii. Reflected voltage and incident voltage is equal. iii. If reflected voltage=20V and incident voltage=10V. iv. If reflected voltage=10V and incident voltage =20V.

Answer : reflection coefficient R=Vr/Vi i. There is no reflected voltage. i.e,Vr=0 R=0 SWR= 1+R/1-R=1 ii. Reflected voltage and incident voltage is equal. Vr=Vi; R=1 SWR= 1+R/1-R=1+1/1-1=infinity iii. If reflected ... and incident voltage =20V. Vr=10 and Vi=20 R=10/20=0.5 SWR= 1+R/1-R=1+.5/1-.5=3

Description : For transmission line, the incident voltage Ei = 6V, and Er = 3V. Calculate: (1) Reflection coefficient (2) Standing wave ratio

Answer : (1)Reflection coefficient  (2) Standing wave ratio (1)Reflection coefficient Reflection coefficient R=Er/Ei  =3/6  R=0.5 (2) Standing wave ratio SWR=Ei+Er/Ei-Er  =6+3/6-3  SWR =3

Description : For a transmission line, the incident voltage. Ei = 6V and Er =2V ,Calculate: (i) Reflection Coefficient (ii) SWR

Answer : Reflection Coefficient(K) = Er / Ei  = 2V / 6V  K = 0.333 SWR = 1+K / 1- K  = 1+0.333 / 1-0.333  = 1.333 / 0.667 SWR= 1.998

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

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.

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

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

Description : State and explain the types of noise in communication system.

Answer : External Noise:  Atmospheric Noise  Atmospheric noise or static is caused by lighting discharges in thunderstorms and other natural electrical disturbances occurring in the atmosphere. These ... between two or more paths, and results from the random fluctuations in the division.

Description : A load of 200 ohm is used to match 300 ohm transmission line to achieve SWR=1. Find out the required characteristic impedance of a quarter of a quarter wave transformer connected directly to the load.

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

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:

Description : Draw general equivalent circuit of transmission line.

Answer : Fig. General Equivalent circuit of transmission line

Description : The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.

Answer : The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.

Description : Draw the structure and state applications of: i) Ferrite loop (rod) antenna ii) Horn antenna

Answer : Horn antenna: Application:- i) Used at microwave frequency. ii) Used in satellite tracking.  Ferrite loop antenna: Application:- In Am radio receiver to receive MW and SW band signals. In FM radio receiver

Description : State the frequency range for audio frequency and voice frequency.

Answer : The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, The usable voice frequency band ranges from approximately 300 Hz to 3400 Hz.

Description : Draw block diagram of basic electronic communication system and state the function of each block.

Answer : i) Input signal: - The information can be in the form of sound, picture or data coming from computer. ii) Input transducer: - it converts original information into equivalent electrical ... back to suitable form. vii) Output transducer: - It converts electrical signal into original form.

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

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.

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

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-

Description : Draw block diagram of FM receiver and explain the use of limiter circuit.

Answer : Diagram Explanation 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.

Description : Explain working of envelope detector with suitable diagram and waveform.

Answer : Envelope Detector: An Envelope Detector is an electronic circuit that takes a high frequency signal as input and provides an output which is as envelopes of the original signal. The capacitor ... decreases the responsiveness thus, real-world designs must be optimized for the application.

Description : Draw construction of Yagi-Uda antenna and explain.

Answer : Explanation A Yagi-Uda antenna, commonly known as a Yagi antenna, is a directional antenna consisting of multiple parallel elements in a line, usually half-wave dipoles made of ... receiver with a transmission line and additional parasitic elements called reflector and one or more directors.

Description : Draw and explain block diagram of electronic communication system.

Answer : Block diagram of electronic communication system. Explanation Transducer: A transducer is usually required to convert the output of a source into an electrical signal that is suitable for ... etc. Output Transducer: The output transducer converts electrical signal in to sound signal.

Description : Explain how modulation reduces height of antenna and avoid mixing of signals.

Answer : Modulation reduces antenna height: For the transmission of radio signals, the antenna height must be multiple of λ/4 ,where λ is the wavelength . λ = c /f where c : is the ... will occupy different slots in the frequency domain (different channels). Thus, modulation avoids mixing of signals.

Description : Draw and explain PLL as an FM demodulator.

Answer : Explanation:- FM signal which is to be demodulated is applied to input of PLL.VCO output must be identical to input signal if PLL is to remain locked. As PLL is locked, VCO ... error voltage represents the modulating signal. Thus at the error amplifier output we get demodulated FM output.

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

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.

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

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

Description : Explain any four different frequency bands and give their two applications of each.

Answer : Explain any four different frequency bands and give their two applications of each.

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

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.

Description : Draw the circuit diagram of practical diode detector and explain its working.

Answer : Circuit diagram of practical diode detector:  Explanation- The circuit operates in the following manner- The diode has been reversed so that now the negative envelope is demodulated. Due to this ... to produce AGC voltage. The DC AGC voltage is proportional to the amplitude of AM signal.

Description : Explain standing waves with load terminal open circuited and short circuited.

Answer : Standing waves with load terminal open circuited   Standing waves: The forward and reflected waves on the incorrectly terminated transmission line produce an interference pattern known as Standing ... , the load impedance will not be equal to the transmission line (characteristic)impedence.

Description : Draw the circuit diagram of limiter and explain its working.

Answer : Circuit diagram of amplitude limiter:- Explanation:- 1. In frequency modulation, the signal amplitude is held constant while the carrier frequency is varied. 2. Any noise that contaminates ... V p-p instead of the alternately driven into saturation and cutoff, it limits the signal amplitude

Description : Draw the TRF receiver block diagram and explain its working.

Answer : Explanation:- 1. TRF receivers are simple and having high sensitivity. The AM transmission takes place in MW band and SW band. MW frequency range is 540KHz to 1640KHz. 2. ... power level to drive the loudspeaker. 7. The loudspeaker converts electrical signal into original sound information.

Description : Draw the circuit diagram of varactor diode FM modulator and explain its working.

Answer : Varactor diode modulator is the direct method of FM generation wherein the carrier frequency is directly varied by the modulating signal. A varactor diode is a semiconductor diode whose ... the magnitude of frequency change is proportional to the amplitude of the modulating signal voltage.

Description : List and explain the properties of quarter wave transformer.

Answer : Properties of quarter wave transformer: 1. Impedance transfomation: it provides impedance transformation upto the highest frequencies and is compatible with transmission line. 2. Impedance inversion: if ZL is ... or step up transformer,depending on whether ZL IS greater than or less than ZO.

Answer : Disadvantages of TRF Receiver: 1. Instability due to oscillatory nature of RF amplifier. 2. Variation in bandwidth over tuning range. 3. Insufficient selectivity at high frequencies 4. Poor adjacent channel rejection capability

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

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

Description : State the process FM detection? State it‟s any two types.

Answer : FM detection: In any radio that is designed to receive frequency modulated signals there is some form of FM demodulator or detector. This circuit takes in frequency modulated RF signals and takes the ... 3. Ratio Detector 4. Phase Discriminator 5. FM Detector using Phase Locked Loop (PLL)

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

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.

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

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:-

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

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

Description : Draw the circuit diagram of PWM using IC555. State its operation.

Answer : Operation: i. The timer IC555 is operated in monostable mode. ii. The negative going carrier pulses are to the differentiator formed by R1 & C1. The differentiator produces sharp negative ... . Thus PWM signal is generated at the output pin (3) of IC555 as monostablemultivibrator.

Description : Define pulse modulation. State its types.

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

← Prev Question Next Question →