01.09.2014 Views

Project Cyclops, A Design... - Department of Earth and Planetary ...

Project Cyclops, A Design... - Department of Earth and Planetary ...

Project Cyclops, A Design... - Department of Earth and Planetary ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Define Nowlets(t) be a sinusoidal signal such that<br />

Qn(x) = s_x +(2n-1)b/2] (b)V rect<br />

S(_)= _(co- _o).<br />

<strong>and</strong><br />

Then<br />

Pn(V) =<br />

{y - _h - (2_ - l)c.] }, rect (-_)<br />

G(u,v) = Vab sine (_) sine b(v _-_)<br />

X<br />

Then<br />

exp<br />

(-]nhv._<br />

N<br />

n=l<br />

[ booo ncv._<br />

expj 2.-1) -- V+<br />

G(u,v) = _ Qn(x)exp Xf ux dx<br />

n=l<br />

The displayed intensity pattern is<br />

x f_f_ en0')exp -121r V vy ay<br />

l(u'v)=lG(u'v)lZ=(Vab)2 sine2 (_'_) sinc2_-_ -b_°)27rV<br />

N<br />

N<br />

The first integral yields<br />

X _.. exp_(2n-1)_]<br />

n=l<br />

n=l<br />

exp [-j(2n - 1)_ ]<br />

Vb sine(_), { expln(2n_f l,bu] Skxf(27rVu)l/I<br />

where<br />

<strong>and</strong> the second<br />

gives<br />

asine exp _ [h-(2n-l)c]v<br />

}<br />

where sinc(_) = sin n/j/rr_ <strong>and</strong> S(w) is the spectrum <strong>of</strong><br />

S(t).<br />

Thus<br />

G(u,v) =<br />

N<br />

Vab sinc (_f) _<br />

n=l<br />

o<br />

2V<br />

The product <strong>of</strong> the two series is equal to sin2NO/sin20<br />

which has narrow (for large n) peaks at 0 = _r,<br />

= 0, -+1,... The u coordinate <strong>of</strong> the bright spots is<br />

u = (?vc/2rrV)6o0 <strong>and</strong> the width <strong>of</strong> the spot between first<br />

zeros is 2_f[b. The u coordinate <strong>of</strong> these spots gives<br />

coarse frequency information. In the v direction a comb<br />

function with a sinc 2 envelope is obtained. The distance<br />

between zeros <strong>of</strong> the sine 2 function is 2hf/a; the comb<br />

peaks occur at<br />

c<br />

2zrV/<br />

exp _ [h-(2n- l)clv<br />

<strong>and</strong> have a spacing <strong>of</strong> _f/c. Since a < c, the envelope<br />

width is greater than the comb spacing. Thus, within<br />

Ivl < hf/2c there is one comb spike at a time. The location<br />

230

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!