Driving an LED

C

Confused Soul

Guest
Hello Everyone,

I am a novice in Electronic Design. I need to drive an LED depending on
the signal I am getting out of a modem. The modem gives the output as
two different frequence (ie FSK modulated). I wanted to know different
ways to do this. As of now, I could come up with the following ideas.

1)
Vcc
|
|
|
/
\ Rc
/
|------------
Rb C
o/p of modem -----/\/\/\/----B (NPN) LED
E
|
|------------
|
|
GND

2)
Vcc
|
|
|
/
\ Rc
/
---
LED
---
|
|
Rb C
o/p of modem -----/\/\/\/----B (NPN)
E
|
|
|
|
GND

3) Another way, I was thinking of using an opamp, in which case i can
operate the LED in linear region and vary the amplitude. But the
frequency seems to be a limit.

In case 1 and 2, the LED is operated in Saturation and cutoff (like a
switch).

Is there any better ways of doing this? Please suggest me ... any
materials/links related to this wud be helpful.

Regards,
ConfusedSoul
 
The LED is supposed to indicate the digital data for eg....FSK output
freq1 as 0 and output freq2 as 1. ... this is in the switching
mode....where i get the digital data.

In case of the transistor acting in linear region, i want to see the
intensity varying.
 
"Confused Soul" <confused.mind@gmail.com> wrote in message
news:ch5hl3$bhq@odbk17.prod.google.com...
The LED is supposed to indicate the digital data for eg....FSK output
freq1 as 0 and output freq2 as 1. ... this is in the switching
mode....where i get the digital data.
Click to expand...
That is what a modem is for, right? What will you be driving the data
from -- the digital data or the FSK?
 
On 1 Sep 2004 14:03:14 -0700, "Confused Soul" <confused.mind@gmail.com>
wrote:

Hello Everyone,

I am a novice in Electronic Design. I need to drive an LED depending on
the signal I am getting out of a modem. The modem gives the output as
two different frequence (ie FSK modulated). I wanted to know different
ways to do this. As of now, I could come up with the following ideas.
Click to expand...
Here's a handy tool for creating ASCII circuit diagrams. MUCH easier
than fighting to do it in a text editor:

http://www.tech-chat.de/AAcircuit.html

--
Rich Webb Norfolk, VA
 
I will be driving the LED from the FSK modulated output.
 
RE: << I will be driving the LED from the FSK modulated output. >>

I'm having trouble driving my LED. The wheels won't stay on the axels.
 
I will be driving the LED from the FSK modulated output.
Click to expand...
For optical communication, or to look at? Until just now I assumed you
wanted a visible display. Or are you using it to transmit data?

It will look the same to the eye at either frequency.
 
On 1 Sep 2004 14:03:14 -0700, "Confused Soul"
<confused.mind@gmail.com> wrote:

I am a novice in Electronic Design. I need to drive an LED depending on
the signal I am getting out of a modem. The modem gives the output as
two different frequence (ie FSK modulated).
Click to expand...
you need a very narrow band audio filter IMHO 2-band for 1,1Khz &
2,1kHz to separate 0 & 1 signal (not sure about frequencies) first;
than IMHO aplify it to drive LEDs ... you can not do it directly IMHO
--
Regards, SPAJKY ÂŽ
& visit my site @ http://www.spajky.vze.com
"Tualatin OC-ed / BX-Slot1 / inaudible setup!"
E-mail AntiSpam: remove ##
 
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