- #1
jerin_007
- 6
- 0
Homework Statement
For a mobile receiver operating at a frequency of 900MHz and moving at 100Km/hr.
Homework Equations
Find Doppler frequency.
How Is Doppler Frequency Calculated for a Mobile Receiver?
Click For Summary
Discussion Overview
The discussion revolves around calculating the Doppler frequency for a mobile receiver operating at a frequency of 900 MHz and moving at a speed of 100 km/hr. Participants explore the relevant equations and concepts related to the Doppler effect, specifically in the context of a homework problem.
Discussion Character
- Homework-related
- Technical explanation
- Exploratory
Main Points Raised
- One participant requests assistance in finding the Doppler frequency, indicating a lack of clarity on the specific formula needed.
- Another participant suggests that the direction of motion (whether redshifting or blueshifting) is crucial for determining the appropriate formula to use.
- A different participant proposes a formula for calculating the frequency based on the speed of sound and the speed of the mobile phone, but notes that the context of motion is important.
- There is mention of Doppler spread, but the participant expresses uncertainty about how to calculate Doppler frequency specifically.
- One participant encourages searching online for information about the Doppler shift or effect, implying that resources may be available to clarify the topic.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the specific formula to use for calculating Doppler frequency, and there are multiple viewpoints regarding the direction of motion and its impact on the calculation.
Contextual Notes
There is an absence of specific equations provided by the original poster, and the discussion reflects uncertainty about the correct approach to the problem. The relevance of the speed of sound and the direction of motion is highlighted but not fully resolved.
For a mobile receiver operating at a frequency of 900MHz and moving at 100Km/hr.
Find Doppler frequency.
- #2
tiny-tim
Science Advisor
Homework Helper
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Welcome to PF!
Hi jerin_007! Welcome to PF!
Show us what you've tried, and where you're stuck, and then we'll know how to help!
Hi jerin_007! Welcome to PF!
Show us what you've tried, and where you're stuck, and then we'll know how to help!
- #3
jerin_007
- 6
- 0
Its just a single formula.. I need to know that.
- #4
tiny-tim
Science Advisor
Homework Helper
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- 258
ok …
then what equations has your professor given you on the subject (or what equations does your book give you)?
and which of those equations do you think will work in this case?
then what equations has your professor given you on the subject (or what equations does your book give you)?
and which of those equations do you think will work in this case?
- #5
jerin_007
- 6
- 0
If that so.. i could have found it.. All i know is how to find doppler spread.. But doppler frequency i can't think of and it isn't there in the book.
- #6
Mark44
Mentor
- 38,110
- 10,674
You obviously have access to a computer with an internet connection. Search for Doppler shift or Doppler effect, and see what you find.
- #7
phycud
- 1
- 0
This looks like a simple doppler shift problem:
you should state which direction of motion the moblie phone is in, this determines whether the the phone is redshifting or blueshifting, so that we know what formulas to use.
i'm going to guess you're dropping the mobile phone down something, which means redshifting.
Which should be (correct me if I'm wrong): f1 = f(C1/(C1+Vs))
Where C1 = Speed of sound (343 ms-1)
f = is the original frequency (900hz)
Vs = the speed of the source (mobile phone 100km/hr)
f1 = new frequency
The phone is redshifting therefore the frequency will be less, i'll let you work the rest out.
quite interesting too, i have an exam question similar to this that is very soon.
you should state which direction of motion the moblie phone is in, this determines whether the the phone is redshifting or blueshifting, so that we know what formulas to use.
i'm going to guess you're dropping the mobile phone down something, which means redshifting.
Which should be (correct me if I'm wrong): f1 = f(C1/(C1+Vs))
Where C1 = Speed of sound (343 ms-1)
f = is the original frequency (900hz)
Vs = the speed of the source (mobile phone 100km/hr)
f1 = new frequency
The phone is redshifting therefore the frequency will be less, i'll let you work the rest out.
quite interesting too, i have an exam question similar to this that is very soon.
- #8
jerin_007
- 6
- 0
Thanks phycud...
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