# Draw the block diagram of FM super heterodyne radio receiver with waveforms.

Draw the block diagram of FM super heterodyne radio receiver with waveforms.

## Related questions

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 : Draw the block diagram of AM. Super heterodyne ratio receiver and state the function of each block

Answer : AM super heterodyne receiver works on the principle of super heterodyning. In the super heterodyne receiver, the incoming signal voltage is combined with a Signal generated in the receiver. The ... constant output level at the speaker even though the signal strength at the antenna varies.

Description : A super heterodyne AM receiver is tuned to a station operating at 1200 KHz .Find local oscillator frequency and image frequency.

Answer : A super heterodyne AM receiver is tuned to a station operating at 1200 KHz Intermediate frequency is 455KHz. IF frequency=f0-fs Local oscillator frequency is f0=IF +fs=455K+1200K=1655kHz The image frequency which gives the same IF is f0+2*IF=2110KHz

Description : Describe the block diagram of FM superhetrodyne receiver

Answer : RF amplifier:- There are two important functions of RF amplifier: 1) To increase the strength of weak RF signal. 2) To reject image frequency signal. In FM broadcast the ... FM broadcast, the maximum modulating frequency is 15 kHz. Hence the audio amplifier must have large bandwidth.

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

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:

Description : Explain with block diagram of Armstrong method of FM generation.

Answer : Explanation:- The crystal oscillator generates the carrier at low frequency typically at 1 MHz this is applied to the combining network and a 90o phase shifter. The modulating signal is passed through an ... power amplifier to raise the power level of the FM signal.  Phasor Diagram:-

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 : Compare TRF and super heterodyne receivers.

Description : State the super heterodyne principle.

Answer : The process of mixing two signals having different frequencies to produce a new frequency i.e., to convert all the incoming frequencies to a lower frequency known as intermediate frequency (IF) . The super heterodyne principle is based on frequency conversion or frequency down conversion.

Description : Draw neat block diagram of FM receiver and explain function of each block

Answer : Explanation:-  RF amplifier: There are two important functions of RF amplifier: 1) To increase the strength of weak RF signal. 2) To reject image frequency signal. In FM ... FM broadcast, the maximum modulating frequency is 15 kHz. Hence the audio amplifier must have large bandwidth.

Description : A superheterodyne radio receiver with an IF of 455KHZ is turned to 1000KHZ. Find: (i) Image frequency (ii) Local oscillator frequency

Answer : Given Intermediate Frequency fi=455KHz Signal frequency =fs=1000KHz Local oscillator frequency fo=fs+fi  Fo=1000KHz+455KHz  =1455KHz Image frequency is the input frequency which produces the same intermediate frequency fsi=fs+2fi  =1000KHz+2*455KHz  =1910KHz

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 : State the IF frequency and bandwidth of FM receiver.

Description : Describe the functions of mixer and local oscillator in radio receiver

Answer : Frequency Mixer:- The function of frequency mixer is to heterodyne signal frequency fs and local oscillator frequency fo. At the output, it produces the difference frequency known as ... local oscillator frequency fo is then mixed with incoming frequency to give intermediate frequency.

Answer : Drawbacks 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 : Explain the following characteristics of AM radio receiver: (i) Sensitivity (ii) Selectivity.

Answer : Sensitivity:- The ability to amplify the weak signals is called sensitivity. It is the function of overall receiver gain. Sensitivity of radio receiver is decided by the gain of the RF IF ... perfectly the receiver is able to select the desired carrier frequency and reject other frequencies.

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 : 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 the block diagram of PWM. List its advantages

Answer : Block diagram of PWM:- Advantages of PWM:- 1. More immune to noise. 2. Synchronization between transmitter and receiver is not required. 3. Possible to separate out signal from noise.

Description : Draw the block diagram of AM transmitter, explain its operation.

Answer : AM transmitter is of two types i)High Level AM Transmitter ii)Low Level AM Transmitter i) RF crystal oscillator: It is a source of carrier signal of desired frequency. The circuit is ... AM signal is then applied to the transmitting antenna which radiates this AM signal into air or space.

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

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.

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 : 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 : Draw the block diagram of PCM receiver with the help of relevant wave form and explain its working

Answer : Block diagram of PCM receiver:- Explanation:- A PCM signal contaminated with noise is available at the receive input. The regeneration circuit at the receiver will separate PCM pulses from noise ... quantized PAM signal is passed through a low pass filter recovers the analog signal x (t).

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

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.

Description : Describe the block diagram of basic communication system.

Answer : Describe the block diagram of basic communication system.

Description : Draw the block diagram of regulated power supply, explain function of each block and draw waveforms of each stage.

Answer : 1. A step down transformer 2. A rectifier 3. A filter 4. A regulator Operation of Regulated Power Supply:- Step Down Transformer:- A step down transformer will ... regulator. A regulator will maintain the output constant even when changes at the input or any other changes occur.

Description : Draw block diagram of PLL as a FM demodulator. Explain function of each block.

Answer : Operation:  The FM signal which is to be demodulated is applied at the input of the PLL.  the PLL is locked to the FM  The error voltage produced at ... using PLL ensures a high Linearity, between the instantaneous input frequency and VCO control voltage (error amplifier output)

Description : Draw and label the circuit diagram of ratio detector

Answer : Draw and label the circuit diagram of ratio detector

Description : Draw circuit diagram of transistor reactance modulator. Explain its working.

Answer : Explanation- A reactance modulator is illustrated in figure. It is basically a standard commonemitter class A amplifier. Resistors R1 and R2 from a voltage divider to bias ... frequency, whereas a lower capacitance increases the frequency. The circuit produces direct frequency modulations.

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 : 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 : 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 diagram for PAM generation using transistors. Explain its working.

Answer : Explanation:-1. Transistor Q1 is used in the active region so it has been provided with DC biasing to its base. 2. Modulating signal is applied to the base of transistor Q1 3. In the emitter of ... . 7. In the time interval between sampling pulses output is zero. Thus we get the output as PAM.

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 : Why should local oscillator frequency be greater than signal frequency in AM receiver? Also explain why IF has constant value?

Answer : Reason for LO frequency to be greater than signal frequency The local oscillator frequency (f0) is made greater than signal frequency (Fs) in radio receiver: Local oscillator frequency range is 995 ... frequency of desired signal because the IF is constant and same for all the incoming RF signal.

Description : Define selectivity and sensitivity of AM Receiver.

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.

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 : Explain reactance modulator for FM generation.

Answer : Explanation :- Audio modulating signal is applied to Q1 which varies the base voltage and current of Q1 according to the input information to be transmitted. The collector current ... lower the frequency & decrease capacitance increase the frequency and thus produce direct FM at output.

Description : Give the expression for modulation index for AM and FM.

Answer : 1.Modulation index for AM ma=Vm / Vc Where Vm is modulating voltage Vc is the carrier voltage 2.Modulation index for FM mf=δ /fm where δ is the deviation fm is 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 : What are the different types of FM detector?

Answer : The different types of FM Detectors are: 1. Simple Slope Detector 2. Balanced Slope Detector 3. Ratio Detector 4. Phase Discriminator 5. FM Detector using Phase Locked Loop (PLL)

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

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

Description : List the types of FM detector. Explain any one of them.

Answer : Types of FM detector:- 1. Simple slope detector 2. Balanced slope detector 3. Phase discriminator(Foster seely discriminator) 4. Ratio detector 5. PLL detector Simple ... . If the IF amplitude is sufficiently limited prior to reaching the PLL and the loop is properly compensated

Description : Compare between FM and PM

Answer : PARAMETERS FM PM 1. Variable parameter of carrier. Frequency Phase 2. Variable parameter proportional to modulating voltage.  Frequency deviation Phase deviation.  3. Amplitude ... for transmitted power More Moderate 6. Signal to noise ratio Best Better

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 : 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 : Explain the working of MTI radar with the help of block diagram and with suitable waveforms.

Answer : Explanation : The echo pulse from the target is received by MTI radar antenna. If echo is due to moving target, the echo pulse undergoes a Doppler frequency. The received echo pulses then pass ... for fixed target magnitude and polarity of output will remain the same as shown in figure.

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

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