What is the necessary Q for good AM reception?

[t_n_p]

Homework Statement

AM radio allows a speration of 10kHz between frequencies of different radio stations. Why do AM radio receivers need a large Q? Estimate the Q required for good AM reception.

The Attempt at a Solution

I'm really not sure where to begin!

 

[Astronuc]

What is the relationship between quality factor, Q, and the frequency and the separation of frequency?

First - check one's textbook.

Also refer to -

http://www.diracdelta.co.uk/science/source/q/u/quality factor/source.html

http://en.wikipedia.org/wiki/Q-factor

 

[t_n_p]

It's not in my textbook but I found out that AM radio receivers need a large q-factor to have a sharper resonance. However I can't find Q required for good AM reception. Any suggestions?

 

[andrevdh]

A electronic oscillator produces em waves at a certain frequency. But the waves are not confined to a particular frequency, instead they spread over a range of frequencies. The most intense radiation (largest power output) is at its resonance frequency. The Q factor quantifies this spread in frequencies. If the stations are too close together the signals from the various transmitters will interfere with the reception.

 

[t_n_p]

Thanks for that more thorough explanation. Still don't know what a good Q is for radio reception though -_-"

 

[andrevdh]

The signals from one station should not overlap with the signal from another station. So you use the given frequency difference between stations to check what the minimum Q factor should be at the mid AM frequency transmissions.

 

[andrevdh]

See the graph in the section titled "Physical interpretation of Q"

http://en.wikipedia.org/wiki/Q_factor