Can someone suggest me chips for reciving and transmitting a fm radio between 30-80Mhz.
actually I thing one PLL chip that can work on 85-90Mhz will be fine to me.

thanks ahead....

 

I don't know what do you want to transmit. In case of mono audio signal I suggest you the TDA7000 Philips radio receiver. You have to use it with external 30..80 MHz RC or XTAL oscillator for fixed freq. If jou wants to tune it, then use RC OSC with varicap diodes. For transmitter use a simple RC oscilator, wich can be modulated with varicaps in FM. If you need I can send you a schematics.

 

RC or LC? RC on 30-80MHz will be a real challenge!

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Look at http://www.rohm.com/products/databoo...pdf/index.html

The BH14XX devices should suit your needs. The one version you can program with dip switches, without using a micro

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Thanks for helpping.
In all datasheets delta f = 75Khz when fm=1Khz. and if I need delta f for example 10 or 5 Khz for fm=1khz, how can I choose it????

I need a mono radio. with sensitivety 0.5-0.8 uV.

 

You want narrow band and not wide band. According to the datasheet you can disable the stereo part with a switch. I think if you limit the deviation (there is a pot on the diagram to set this) to 10-15kHz you should be able to receive it OK on a narrow band receiver.

It looks like the output will be low from this chip. About -7dBm. I think you will need some amplifier to get any distance further than about 20' from it.

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where and how can I choose my BW???
and if I will put a 50 om antena, will my sensitivity be around 0.6uV?
and how can I calculate all caps???

 

This chip is only a transmitter. You need another receiver. What are you trying to do, make a transceiver?

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I am talking about tda7000

 

You need to download an application note on how to use the device and calculate the values.

Using a 50-Ohm antenna will cause a mismatch for the chip which appears to have a 75-Ohm input impedance.

0.6uV with acceptable level of distortion ...I don't think so. Maybe with a RF preamp.

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where can I download it???

 

The TDA7000 was made obsolete by Philips so I am not sure where to get it. Search Google, that's all I could do.

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hey zener. i made a tda7000 receiver. here is the link for all my questions and stuff as i was building it: http://www.electro-tech-online.com/v...hlight=tda7000

and here is the link of where i got the plans: http://web.telia.com/~u85920178/

i didnt think that the TDA7000 was all that great of a receiver. the stations that i got w/ it also came in on a clock radio just as good. maybe i just wasnt building it right, i dont know. i am still looking for a very sensitive FM radio for my FM bug that i built.

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I built a tda7000 kit available at my local store. The selectivity is excellent as it is a full super het design. MOving the capacitor 1/2 of a degree caused the station to shift.

It was too selective, in other words!!! Sensitivity on the other hand was down compared to my good' ol sony walkman. especially in the lower frequencies for some reason.

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wut kind of capacitor were u using pike? i used a 2-18 pf cap and i was able to hone in on a certain frequency quite nicely. if i'd used a 0-3 pf cap, i would get an even smaller deviation.

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I'm no electronics god, i just talk too much.