Abstract: According to various embodiments, a circuit for determining the frequency of a signal is described, comprising an input configured to receive an analog input signal, an analog to digital converter configured to convert the analog input signal to a digital input signal, a digital mixer configured to generate a mixing result signal by mixing the digital input signal with a single bit binary signal having a reference frequency, a low pass filter configured to generate a filtered signal by filtering the mixing result signal, a measuring circuit configured to measure the period of the filtered signal and an output configured to output a value differing from the frequency of the single bit binary signal by the inverse of the measured period as the frequency to be determined.

Abstract: The invention relates to a method for stocking and preserving green round wood and sawn timber, which is stored in an airtight and lighttight sealing cover. The oxygen inside the cover is decomposed by the respiratory process of fungi, bacteria and wood cells that are still alive, thereby forming CO2 and H2O. Fermentation processes also lead to the decomposition of hemicelluloses and saccharides which are converted to organic acids and CO2. The oxygen content in the cover is less than 0.1 vol. % after an adjustment time of 3 to 10 days of total stocking, while said CO2 content rises to more than 21 and up to 40 vol. %. This method enables green round wood a swan timber to be stocked over long periods without wastage or environmental damage.