Fwd: a question about pull_in function in the open code

Hi,

I have a question when reading the open code for GPSISR: ch_pull_in ().

In the PLL part in pull_in state,
"  q_sum = c->accum.q_dith + c->accum.q_prompt;
 i_sum = c->accum.i_dith + c->accum.i_prompt;
 if (i_sum != 0 || q_sum != 0)
   theta = fix_atan2 (q_sum, -i_sum); "

Is fix_atan2 (q_sum, -i_sum) the phase detecter?
Why  Q=q_sum & I=-i_sum are used instead of Q=c->accum.q_prompt & I =
c->accum.i_prompt;

Sorry for the mistake in last email.
Thanks again

//tongtong

---------- Forwarded message ----------
From: tongtong wang <[email protected]>
Date: May 21, 2007 6:53 PM
Subject: a question about pull_in function in the open code
To: [email protected]


hi, there
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//tongtong