Context : Atmospheric properties of F- , G- and K-type stars can be measured by spectral model fitting or from the analysis of equivalent width measurements .
These methods require data with good signal-to-noise ratio and reliable continuum normalisation .
This is particularly challenging for the spectra we have obtained with the CORALIE échelle spectrograph for FGK stars with transiting M-dwarf companions .
The spectra tend to have low signal-to-noise ratios , which makes it difficult to analyse them using existing methods .

Aims : Our aim is to create a reliable automated spectral analysis routine to determine T _ { eff } , [ Fe/H ] , V \sin i from the CORALIE spectra of FGK stars .

Methods : We use wavelet decomposition to distinguish between noise , continuum trends , and stellar spectral features in the CORALIE spectra .
A subset of wavelet coefficients from the target spectrum are compared to those from a grid of models in a Bayesian framework to determine the posterior probability distributions of the atmospheric parameters .

Results : By testing our method using synthetic spectra we found that our method converges on the best fitting atmospheric parameters .
We test the wavelet method on 20 FGK exoplanet host stars for which higher quality data have been independently analysed using equivalent width measurements .
We find that we can determine T _ { eff } to a precision of 85 K , [ Fe/H ] to a precision of 0.06 dex and V \sin i to a precision of 1.35 km s ^ { -1 } for stars with V \sin i \geq 5 km s ^ { -1 } .
We find an offset in metallicity \approx - 0.18 dex relative to the equivelent width fitting method .
We can determine \log g to a precision of 0.13 dex but find systematic trends with T _ { eff } .
Measurements of \log g are only reliable to confirm dwarf-like surface gravity ( \log g \approx 4.5 ) .

Conclusions : The wavelet method can be used to determine T _ { eff } , [ Fe/H ] and V \sin i for FGK stars from CORALIE échelle spectra .
Measurements of \log g are unreliable but can confirm dwarf-like surface gravity .
We find that our method is self consistent , and robust for spectra with SNR \gtrapprox 40 .