Re: Estimating the FM frequency at which a receiver is tuned



sasuke wrote:
Hello

I am thinking of a project described as follows. Imagine a person
traveling in a car listening to radio on a particular FM channel. For now
assume that there is an antenna on top of the car receiving this FM signal.
Let's say that there is a device placed inside the car with antennas
attached to it. Without any connection to the default FM receiver in the
car, I want to estimate the channel at which the user is tuned to.

This is simple: just receive the parasitic emission from the receiver heterodyne and find the frequency; so you know the channel. Systems like that have been in use for the estimation of the popularity of the FM channels since long ago. BTW, you can receive the heterodyne at some distance from the car without notifying the driver.


I have thought up a way but I am not sure if I have missed something
important. What I have thought of is to have the device receive on all
active FM channels(now here I have made a possibly naive assumption that at
a given time there maybe at most 25 active FM channels over the entire FM
spectrum). The received audio data is stored in digital format on the
device itself. I have a small microphone placed very close to the speaker
in the car, which also goes to this device and sits in it's own memory.
Once I have all these digital samples available, I intend to run a simple
data correlation between the samples from the microphone and the samples I
have collected using my device. The set of samples which correlate the most
with the data from microphone indicates the frequency at which the user was
listening, when the data from microphone was collected. Now I know that
this hypothetical device I have described will require a lot of processing
power and antennas to listen over the entire FM spectrum. For now I am
disregarding this constraint. Can someone tell me if the method I have
described above is feasible?

Unnecessary overcomplication and major inconveniece.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com


.

Relevant Pages

  • Radio fox
    ... Today I had to rent a car "Caravan', ... even an Elvis channel. ... the darn fools in Court when they can't prove who/what is responsible. ...
    (misc.news.internet.discuss)
  • Re: Estimating the FM frequency at which a receiver is tuned
    ... traveling in a car listening to radio on a particular FM channel. ... assume that there is an antenna on top of the car receiving this FM signal. ... I have a small microphone placed very close to the speaker ...
    (comp.dsp)
  • Re: Estimating the FM frequency at which a receiver is tuned
    ... traveling in a car listening to radio on a particular FM channel. ... assume that there is an antenna on top of the car receiving this FM signal. ... I want to estimate the channel at which the user is tuned to. ... I have a small microphone placed very close to the speaker ...
    (comp.dsp)
  • Estimating the FM frequency at which a receiver is tuned
    ... traveling in a car listening to radio on a particular FM channel. ... assume that there is an antenna on top of the car receiving this FM signal. ... I want to estimate the channel at which the user is tuned to. ... I have a small microphone placed very close to the speaker ...
    (comp.dsp)
  • Re: Estonian Question
    ... Maris wrote: ... You can get to Riga via Ryanair for about £50 return at the ... Crossing the channel using Speedferry is also cheap at £19 ... > oneway for a car with five passengers. ...
    (soc.culture.baltics)
Loading