Electronics and Communication Engineering (ECE) Exam  >  Electronics and Communication Engineering (ECE) Questions  >  A continuous-time signal has frequency conten... Start Learning for Free
A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:
  • a)
    10 MHz
  • b)
    10 MHz and 6 MHz
  • c)
    10 MHz, 6 MHz, and 14MHz
  • d)
    46 MHz
Correct answer is option 'C'. Can you explain this answer?
Most Upvoted Answer
A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, ...
Answer:

Frequency content of the continuous-time signal: 10 MHz, 50 MHz, and 70 MHz.

Sampling frequency: 56 MHz.

Low-pass filter cutoff frequency: 15 MHz.

Output frequency content after passing through the low-pass filter: 10 MHz, 6 MHz, and 14 MHz.

Explanation:

The Nyquist-Shannon sampling theorem states that a continuous-time signal can be perfectly reconstructed from its samples if the sampling frequency is greater than twice the highest frequency component of the signal. In this case, the highest frequency component of the signal is 70 MHz. Therefore, the sampling frequency of 56 MHz is sufficient to capture all the frequency content of the signal.

However, since the sampling frequency is less than twice the frequency of the highest component of the signal, aliasing can occur. Aliasing is the phenomenon where high-frequency components of the signal are folded back into the frequency band of the lower-frequency components.

To prevent aliasing, a low-pass filter is used to remove the high-frequency components of the signal before sampling. In this case, a low-pass filter with a cutoff frequency of 15 MHz is used.

The low-pass filter removes all frequency components above 15 MHz, including the 50 MHz and 70 MHz components of the original signal. The only frequency component that remains is the 10 MHz component.

However, since the original signal had frequency components at 10 MHz, 50 MHz, and 70 MHz, the low-pass filter output will also contain frequency components due to aliasing. These alias frequencies are given by:

- 2 × 56 MHz – 70 MHz = 42 MHz (alias of 70 MHz)
- 2 × 56 MHz – 50 MHz = 62 MHz (alias of 50 MHz)

Therefore, the frequency content of the output of the filter will be 10 MHz (due to the original 10 MHz component) and 6 MHz and 14 MHz (due to aliasing of the original 50 MHz and 70 MHz components, respectively). The correct answer is option 'C'.
Free Test
Community Answer
A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, ...
Calculation:
fs = Sampling Frequency = 56 MHz
The frequencies present at the input are:
fm1 = 10 MHz, fm2 = 50 MHz and, fm3 = 70 MHz
Once sampled, the frequency content at the output will be: fm ± fs
For, fm1 = 10 MHz, the output will contain frequencies of,
= fm1, fm1 ±, fm1 ± 2fs ….
= 10 MHz, 66 MHz, 122 MHz
For, fm2 = 50 MHz, the output will contain frequencies of
= fm2, fm2 ± fs, fm2 ± 2fs ….
= 50 MHz, 6 MHz, 106 MHz, 162 MHz
For, fm3 = 70 MHz, the output will contain frequencies of
= fm3, fm3 ± fs, fm3 ± 2fs ….
= 70 MHz, 14 MHz, 182 MHz ….
When these frequencies are passed through a low pass filter with a cutoff frequency of 15 MHz, the only remaining frequencies at its output will be 6MHz, 10 MHz and 14 MHz.
Attention Electronics and Communication Engineering (ECE) Students!
To make sure you are not studying endlessly, EduRev has designed Electronics and Communication Engineering (ECE) study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Electronics and Communication Engineering (ECE).
Explore Courses for Electronics and Communication Engineering (ECE) exam

Top Courses for Electronics and Communication Engineering (ECE)

A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer?
Question Description
A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? for Electronics and Communication Engineering (ECE) 2024 is part of Electronics and Communication Engineering (ECE) preparation. The Question and answers have been prepared according to the Electronics and Communication Engineering (ECE) exam syllabus. Information about A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Electronics and Communication Engineering (ECE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer?.
Solutions for A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Electronics and Communication Engineering (ECE). Download more important topics, notes, lectures and mock test series for Electronics and Communication Engineering (ECE) Exam by signing up for free.
Here you can find the meaning of A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer?, a detailed solution for A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? has been provided alongside types of A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A continuous-time signal has frequency content at f = 10 MHz, 50 MHz, and 70 MHz. The signal is sampled at a sampling frequency of 56 MHz and is then passed through a low-pass filter with a cutoff frequency of 15 MHz. The frequency content of the output of the filter will be:a)10 MHzb)10 MHz and 6 MHzc)10 MHz, 6 MHz, and 14MHzd)46 MHzCorrect answer is option 'C'. Can you explain this answer? tests, examples and also practice Electronics and Communication Engineering (ECE) tests.
Explore Courses for Electronics and Communication Engineering (ECE) exam

Top Courses for Electronics and Communication Engineering (ECE)

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev