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Function: `freq_inject_chirp()`

0
`void freq_inject_chirp(float c0, float c90, int offset, float
invMpc, float* ch0tilde, float* ch90tilde, float* htilde, int n) `

The bottom-line test of any optimal filtering code or searching
routines is: can you inject ``fake" signals into the data stream, and
properly detecting them, while properly rejecting all other signatures
of instrumental effects, etc. This routine injects artificial signals
into the frequency-domain strain . The plane of the binary
system is assumed to be normal to the line to the detector.
The arguments are:

`c0:` Input. The coefficient of the 0-phase template to inject.
`c90:` Input. The coefficient of the -phase to
inject. Note that
should be 1.
`offset:` Input. The offset number of samples at which the injected chirp starts, in the
time domain.
`invMpc:` Input. The inverse of the distance to the system
(measured in Mpc).
`ch0tilde:` Input. The FFT of the phase-0 chirp (strain units)
at a distance of 1 Mpc.
`ch90tilde:` Input. The FFT of the phase-90 chirp (strain units)
at a distance of 1 Mpc.
`htilde:` Output. The FFT of the gravity-wave strain. Note that
this routine *adds into* and increments this array, so that if it
contains another ``signal" like IFO noise, the chirp is simply super-posed
onto it.
`n:` Input. Defines the lengths of the various arrays `ch0tilde[0..n-1]`,
`ch90tilde[0..n-1]`, and `htilde[0..n-1]`.

Note that in making use of this injection routine, you must determine
the level of the quantization noise of the ADC, and be careful to
inject a properly dithered version of this signal when its amplitude
is small compared to the ADC quantization step size.

- Author:
Bruce Allen, ballen@dirac.phys.uwm.edu
- Comments:
See the comments for
`time_inject_chirp`, particularly with respect to
the digital quantization noise.

** Next:** Function: time_inject_chirp()
** Up:** GRASP Routines: Gravitational Radiation
** Previous:** Function: find_chirp()
** Contents**
Bruce Allen
2000-11-19