A description is given of multi-band electrical filters and associated circuits which can be used to simulate numerical methods of computing the magnitude of eddy velocity. The filters are supplied directly with the voltage from a wind sensor, and outputs from the filters are recorded as mean deviations. These are then converted to standard deviations by multiplying by a `form factor'. Evidence of the consistency of the form factor is presented. The equipment may also be used to obtain in `real time' a measure of the power or energy spectrum of wind gusts from a frequency of about 1 cycle per hour up to the cut-off frequency of the sensor.