From: bos1234 on
[IMG]http://i49.tinypic.com/219w36q.png[/IMG]
Question reads:
Give the required value of frequency multiplication, n. Also, fully define
the mixer by giving two permissible frequencies for the local oscillator.

Am I correct in saying that D_1=0.05 and D_2=20?,
However the solution has

Solution:
f_d2=nf_d1
20=n(0.05)
n=400

[IMG]http://i50.tinypic.com/im4083.png[/IMG]

The problem I'm having is what frequency is coming into the multiplier?
100Mhz or 44Khz?
From: Jerry Avins on
On 6/16/2010 11:16 PM, bos1234 wrote:
> [IMG]http://i49.tinypic.com/219w36q.png[/IMG]
> Question reads:
> Give the required value of frequency multiplication, n. Also, fully define
> the mixer by giving two permissible frequencies for the local oscillator.
>
> Am I correct in saying that D_1=0.05 and D_2=20?,
> However the solution has
>
> Solution:
> f_d2=nf_d1
> 20=n(0.05)
> n=400
>
> [IMG]http://i50.tinypic.com/im4083.png[/IMG]
>
> The problem I'm having is what frequency is coming into the multiplier?
> 100Mhz or 44Khz?

There seems to be an error. Both the carrier frequency and the deviation
are multiplied by the same factor, so the deviation ratio is the same
before and after the frequency multiplier. The deviation (not the
deviation ratio) is the same before and after the mixer. Can you take it
from there?

Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
From: Mark on
On Jun 17, 12:35 am, Jerry Avins <j...(a)ieee.org> wrote:
> On 6/16/2010 11:16 PM, bos1234 wrote:
>
>
>
> > [IMG]http://i49.tinypic.com/219w36q.png[/IMG]
> > Question reads:
> >   Give the required value of frequency multiplication, n. Also, fully define
> > the mixer by giving two permissible frequencies for the local oscillator.
>
> > Am I correct in saying that D_1=0.05 and D_2=20?,
> > However the solution has
>
> > Solution:
> > f_d2=nf_d1
> > 20=n(0.05)
> > n=400
>
> > [IMG]http://i50.tinypic.com/im4083.png[/IMG]
>
> > The problem I'm having is what frequency is coming into the multiplier?
> > 100Mhz or 44Khz?
>
> There seems to be an error. Both the carrier frequency and the deviation
> are multiplied by the same factor, so the deviation ratio is the same
> before and after the frequency multiplier. The deviation (not the
> deviation ratio) is the same before and after the mixer. Can you take it
> from there?
>
> Jerry
> --
> Engineering is the art of making what you want from things you can get.
> ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

If "deviation ratio" is taken to mean what most people call BETA
which is DEVIATION/MODULATION FREQ , then it DOES increase going
through the multiplier.

Mark