fix errant extra dhdl definition

gwinc/ifo/noises.py

@@ -124,31 +124,6 @@ def ifo_power(ifo, PRfixed=True):
     power.Tpr = Tpr
     return power
 
-
-def dhdl(f, armlen):
-    """Strain to length conversion for noise power spetra
-
-    This takes into account the GW wavelength and is only important
-    when this is comparable to the detector arm length.
-
-    From R. Schilling, CQG 14 (1997) 1513-1519, equation 5,
-    with n = 1, nu = 0.05, ignoring overall phase and cos(nu)^2.
-    A small value of nu is used instead of zero to avoid infinities.
-
-    Returns the square of the dh/dL function, and the same divided by
-    the arm length squared.
-
-    """
-    c = const.c
-    nu_small = 15*pi/180
-    omega_arm = pi * f * armlen / c
-    omega_arm_f = (1 - sin(nu_small)) * pi * f * armlen / c
-    omega_arm_b = (1 + sin(nu_small)) * pi * f * armlen / c
-    sinc_sqr = 4 / abs(sin(omega_arm_f) * exp(-1j * omega_arm) / omega_arm_f
-                       + sin(omega_arm_b) * exp(1j * omega_arm) / omega_arm_b)**2
-    dhdl_sqr = sinc_sqr / armlen**2
-    return dhdl_sqr, sinc_sqr
-
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