Q1 . Design superhetrodyne receiver with an input of 5khz generated at the transmitter end and
having a carrier frequency of 1MHz. Assume the noiseless channel and explain the output of
each block by plotting a suitable waveforms after each and every block. Also discuss the role of
sensitivity, selectivity, and fidelity while elaborating the receiver end
Answer - A superheterodyne receiver is a popular type of radio receiver used for receiving radio
signals. It uses the principle of mixing two frequencies to produce a third frequency that is the
difference between the two. This third frequency is called the intermediate frequency (IF) and is
easier to amplify and filter than the original radio frequency (RF) signal.
The following is a basic block diagram of a superheterodyne receiver:
In this case, the input signal has a frequency of 5kHz, and the carrier frequency is 1MHz. The receiver
will down-convert the signal to an intermediate frequency of 455kHz.
The following are the various blocks in the receiver and their functions:
1. Antenna: The antenna receives the RF signal and converts it into an electrical signal.
2. RF amplifier: The RF amplifier amplifies the weak electrical signal received from the antenna and
passes it on to the mixer.
3. Mixer: The mixer combines the RF signal with a local oscillator (LO) signal of frequency 1.455MHz to
produce the intermediate frequency signal of 455kHz.
4. IF amplifier: The IF amplifier amplifies the intermediate frequency signal to a level suitable for
detection.
5. Detector: The detector demodulates the signal to extract the original information (in this case, the
5kHz signal).
6. Audio amplifier: The audio amplifier amplifies the demodulated signal and sends it to the
loudspeaker.
The following are the waveforms at various points in the receiver:
The sensitivity of a receiver is a measure of its ability to detect weak signals. In this case, the RF
amplifier is responsible for boosting the weak signal received from the antenna. A highly sensitive
receiver will be able to detect even the weakest of signals.
The selectivity of a receiver is a measure of its ability to separate signals that are close in frequency.
In this case, the mixer is responsible for down-converting the signal to the intermediate frequency,
which is easier to filter and amplify. A highly selective receiver will be able to separate signals that are
close in frequency.
The fidelity of a receiver is a measure of its ability to reproduce the original signal accurately. In this
case, the detector is responsible for demodulating the signal to extract the original information. A
highly faithful receiver will be able to reproduce the original signal accurately.
, Q2. Design Tuned Radio frequency receiver with an input of 15khz generated at the transmitter
end and having a carrier frequency of 100MHz. Assume the noisy channel and explain the
output of each block by plotting a suitable waveform after each and every block. Also discuss
the role of sensitivity, selectivity, and fidelity while elaborating the receiver end.
Answer - A Tuned Radio Frequency (TRF) receiver is another type of radio receiver used
for receiving radio signals. It uses a series of tuned circuits to select and amplify a
narrow band of frequencies.
The following is a basic block diagram of a TRF receiver:
In this case, the input signal has a frequency of 15kHz, and the carrier frequency is
100MHz. The receiver will down-convert the signal to baseband by using a local
oscillator (LO) frequency of 100.015MHz.
The following are the various blocks in the receiver and their functions:
1. Antenna: The antenna receives the RF signal and converts it into an electrical signal.
2. RF amplifier: The RF amplifier amplifies the weak electrical signal received from the
antenna and passes it on to the mixer.
3. Mixer: The mixer combines the RF signal with a local oscillator (LO) signal of frequency
100.015MHz to produce an intermediate frequency (IF) signal of 15kHz.
4. IF amplifier: The IF amplifier amplifies the intermediate frequency signal to a level
suitable for detection.
5. Detector: The detector demodulates the signal to extract the original information (in
this case, the 15kHz signal).
6. Audio amplifier: The audio amplifier amplifies the demodulated signal and sends it to
the loudspeaker.
The following are the waveforms at various points in the receiver:
In a noisy channel, the received signal will be affected by noise and interference, which
can affect the receiver's performance. The sensitivity of the receiver is still important, as
it determines how well the receiver can detect weak signals in the presence of noise.
The selectivity of the receiver is particularly important in a TRF receiver, as it uses tuned
circuits to select and amplify a narrow band of frequencies. The tuned circuits act as
bandpass filters and select the desired frequency while rejecting unwanted frequencies.
A highly selective receiver will be able to reject interference and noise outside the
desired frequency band.
having a carrier frequency of 1MHz. Assume the noiseless channel and explain the output of
each block by plotting a suitable waveforms after each and every block. Also discuss the role of
sensitivity, selectivity, and fidelity while elaborating the receiver end
Answer - A superheterodyne receiver is a popular type of radio receiver used for receiving radio
signals. It uses the principle of mixing two frequencies to produce a third frequency that is the
difference between the two. This third frequency is called the intermediate frequency (IF) and is
easier to amplify and filter than the original radio frequency (RF) signal.
The following is a basic block diagram of a superheterodyne receiver:
In this case, the input signal has a frequency of 5kHz, and the carrier frequency is 1MHz. The receiver
will down-convert the signal to an intermediate frequency of 455kHz.
The following are the various blocks in the receiver and their functions:
1. Antenna: The antenna receives the RF signal and converts it into an electrical signal.
2. RF amplifier: The RF amplifier amplifies the weak electrical signal received from the antenna and
passes it on to the mixer.
3. Mixer: The mixer combines the RF signal with a local oscillator (LO) signal of frequency 1.455MHz to
produce the intermediate frequency signal of 455kHz.
4. IF amplifier: The IF amplifier amplifies the intermediate frequency signal to a level suitable for
detection.
5. Detector: The detector demodulates the signal to extract the original information (in this case, the
5kHz signal).
6. Audio amplifier: The audio amplifier amplifies the demodulated signal and sends it to the
loudspeaker.
The following are the waveforms at various points in the receiver:
The sensitivity of a receiver is a measure of its ability to detect weak signals. In this case, the RF
amplifier is responsible for boosting the weak signal received from the antenna. A highly sensitive
receiver will be able to detect even the weakest of signals.
The selectivity of a receiver is a measure of its ability to separate signals that are close in frequency.
In this case, the mixer is responsible for down-converting the signal to the intermediate frequency,
which is easier to filter and amplify. A highly selective receiver will be able to separate signals that are
close in frequency.
The fidelity of a receiver is a measure of its ability to reproduce the original signal accurately. In this
case, the detector is responsible for demodulating the signal to extract the original information. A
highly faithful receiver will be able to reproduce the original signal accurately.
, Q2. Design Tuned Radio frequency receiver with an input of 15khz generated at the transmitter
end and having a carrier frequency of 100MHz. Assume the noisy channel and explain the
output of each block by plotting a suitable waveform after each and every block. Also discuss
the role of sensitivity, selectivity, and fidelity while elaborating the receiver end.
Answer - A Tuned Radio Frequency (TRF) receiver is another type of radio receiver used
for receiving radio signals. It uses a series of tuned circuits to select and amplify a
narrow band of frequencies.
The following is a basic block diagram of a TRF receiver:
In this case, the input signal has a frequency of 15kHz, and the carrier frequency is
100MHz. The receiver will down-convert the signal to baseband by using a local
oscillator (LO) frequency of 100.015MHz.
The following are the various blocks in the receiver and their functions:
1. Antenna: The antenna receives the RF signal and converts it into an electrical signal.
2. RF amplifier: The RF amplifier amplifies the weak electrical signal received from the
antenna and passes it on to the mixer.
3. Mixer: The mixer combines the RF signal with a local oscillator (LO) signal of frequency
100.015MHz to produce an intermediate frequency (IF) signal of 15kHz.
4. IF amplifier: The IF amplifier amplifies the intermediate frequency signal to a level
suitable for detection.
5. Detector: The detector demodulates the signal to extract the original information (in
this case, the 15kHz signal).
6. Audio amplifier: The audio amplifier amplifies the demodulated signal and sends it to
the loudspeaker.
The following are the waveforms at various points in the receiver:
In a noisy channel, the received signal will be affected by noise and interference, which
can affect the receiver's performance. The sensitivity of the receiver is still important, as
it determines how well the receiver can detect weak signals in the presence of noise.
The selectivity of the receiver is particularly important in a TRF receiver, as it uses tuned
circuits to select and amplify a narrow band of frequencies. The tuned circuits act as
bandpass filters and select the desired frequency while rejecting unwanted frequencies.
A highly selective receiver will be able to reject interference and noise outside the
desired frequency band.
