lmf100

[Marcellus Pereira]

Dear ALL,

I'm having trouble with the National LMF 100.

Does anyone could help me?

Thank you,

Marcellus

 

[The Kid]

Marcellus Pereira <mpereira@myrealbox.com> wrote in message news:<ejagjvcdabjo4m9mitglkpfphvpdg3896v@4ax.com>...

Dear ALL,

I'm having trouble with the National LMF 100.

Does anyone could help me?

Thank you,

Marcellus

Marcellus'

Please give more information about the problem.

Thanks,
The Kid

 

[Marcellus Pereira]

On 12 Aug 2003 19:24:26 -0700, cookingout@netzero.net (The Kid) wrote:

Marcellus Pereira <mpereira@myrealbox.com> wrote in message news:<ejagjvcdabjo4m9mitglkpfphvpdg3896v@4ax.com>...
Dear ALL,

I'm having trouble with the National LMF 100.

Does anyone could help me?

Thank you,

Marcellus


Marcellus'

Please give more information about the problem.

Thanks,
The Kid
Well, I posted o follow-up message, but it desappeared!

After a lot of thinking, I found the problem...

I was trying to do a 60Hz notch filter, following the National LMF100
datasheet example ( figure 23 ). But I had to use a 32,768kHz crystal.

My first calculation was:
R1 100000
R2 3300
R3 536000
R4 100000

Rg 10000
Rh 10000
Ri 1000

My notch filter was *strengthen* the signal at 60Hz!

Now, I use the following:

R1 100000
R2 3300
R3 100000
R4 100000

Rg 10000
Rh 10000
Ri 1000

Thus, the BandPass and HighPass gain are the same ( -1 ). I think this
was the problem. The final attenuation @ 60Hz is now ~17dB.

Can I improve this attenuation?

[]s
Marcellus