Re: [Discuss-gnuradio] Using DSP for precise zero crossing, measurement?

[Lee Patton]

On Mon, 2006-09-18 at 14:08 -0400, Lee Patton wrote:
> On Mon, 2006-09-18 at 12:32 -0400, Achilleas Anastasopoulos wrote:
> > John,
> > 
> > If want to measure the time difference between two sine waves in noise 
> > and accuracy is your primary objective, then you should start with the
> > "optimal" solution to the problem and not with an ad-hoc technique
> > such as measuring the zero crossings.
> > 
> > In the simplest scenario, if your model looks like:
> > s(t) = s(t;A1,A2,t1,t2) = A1 sin(w (t-t1)) + A2 sin(w (t-t2))
> > r(t)=s(t)+n(t)
> 
> John, 
> 
> Does your model look like the one Achilleas described above, or is it
> like the following? 
> 
> s1(t) = A1*sin(w1(t-t1)+phi1); r1(t) = s1(t) + n1(t)
> s2(t) = A2*sin(w2(t-t2)+phi2); r2(t) = s2(t) + n2(t)

whoops. should have been 

s1(t) = A1*sin(w1*t + phi1) or A1*sin(w1*(t-t1))
s2(t) = A2*sin(w2*t + phi2) or A2*sin(w2*(t-t2))

but you get the point...