The probability distribution for the ratio of variables having a normal distribution

"The probability density function is derived for the ratio of two independent random variables, each of which has a normal distribution. When the variances of the normal distributions are small, a simplifying approximation to the probability density function for the ratio of the two variables is valid; the lower tail of the approximate distribution is approximately normal. This result validates the bias-correction calculation for minimum-envelope processing of skywave radar sea-echo spectra presented in a previous report. The distribution function for the ratio approaches a normal distribution as the variances for the numerator and denominator distributions approach zero, in agreement with previous, related calculations."