PlaneMad
New Member
This is part of a small college project that im doing where i plan to make a simpsystem which will tell passengers inside a train what station is coming up next.
So heres how i thought it would work (the emphasis of the project is on simplicity)
Each station transmits different tone frequencies using fm. So station1 has 1KHz, station2 has 2Khz. (same carrier but different mod frequency)
In the train the tone is demodulated from the carrier and fed to a frequency voltage convertor. So now each time it passes through a station , we get a particular voltage, say 1V for station1 and 2V for station2 etc. I plan to use a total of 8 different tones, so 8 different voltage levels.
This dc voltage is converted into a digital code using a adc chip, after which it will be fed to a 3:8 decoder and light up an LED status board for the corresponding station.
I want to know if this is practicall possible to implement. we already have a tuned fm tx/rx system where we can demodulate the tone that was transmitted. im stuck at the fvc section. initially i tried building a circuit using the xr4151 ic but that didnt work. after some googling ive found that you have another simpler ic lm2917 which im planning to use. will that do the job?
im still an elec newb, so be soft on me.
thanks![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
So heres how i thought it would work (the emphasis of the project is on simplicity)
Each station transmits different tone frequencies using fm. So station1 has 1KHz, station2 has 2Khz. (same carrier but different mod frequency)
In the train the tone is demodulated from the carrier and fed to a frequency voltage convertor. So now each time it passes through a station , we get a particular voltage, say 1V for station1 and 2V for station2 etc. I plan to use a total of 8 different tones, so 8 different voltage levels.
This dc voltage is converted into a digital code using a adc chip, after which it will be fed to a 3:8 decoder and light up an LED status board for the corresponding station.
I want to know if this is practicall possible to implement. we already have a tuned fm tx/rx system where we can demodulate the tone that was transmitted. im stuck at the fvc section. initially i tried building a circuit using the xr4151 ic but that didnt work. after some googling ive found that you have another simpler ic lm2917 which im planning to use. will that do the job?
im still an elec newb, so be soft on me.
thanks