Guillermo P. Garcia Mendive wrote:

>I wonder I anyone can help me. Im trying to receive the signal radiated from a standard
>cardio breast belt. A far as I could check with my scope it produces a 5 Khz sinusoidal
>train lasting 7 miliseconds for each heartbeat. The receiver, inside the wrist watch,
>succesfully receives the pulse even when it is a far as 120 cm. from the transmitter.
>Nonetheless the signal radiated energy at that wavelength must be very low. What kind of
>front end do they use in the receiver, considering any antenna inside the watch should be
>ridiculously small at that frecuency. I suspect theyre using some kind of magnetic loop
>antenna... Any ideas will be welcomed.
>  
>
Yes the largest coil, used for loudspeaker filters, you can find at Farnell,
works perfect.
(Although not so small as the watch ;-)
you can easily reach 4 .. 5 meters

Stef Mientki

> 
>Thanks in advance.
>Bill Mendive
>  
>
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