Abstract: A gamma tap circuit includes: (i) a first gamma division circuit configured to generate a first gamma tap voltage by performing voltage division of an upper gamma tap voltage and a lower gamma tap voltage, in-sync with a first clock signal CK1 and a first complementary clock signal CK1b, which is 180° out-of-phase relative to CK1, (ii) a second gamma division circuit configured to generate a second gamma tap voltage by performing voltage division of the upper gamma tap voltage and the first gamma tap voltage, in-sync with a second clock signal CK2 and a second complementary clock signal CK2b, which is 180° out-of-phase relative to CK2, and (iii) a third gamma division circuit configured to generate a third gamma tap voltage by performing voltage division of the first gamma tap voltage and the lower gamma tap voltage, in response to CK2 and CK2b, which have a lower frequency relative to CK1 and CK1b.

Abstract: The subject invention relates to two-stage inoculation and two-stage fermentation process which are performed by the inoculation time difference and staged fermentation. In the first stage, yeast, lactic acid bacteria and Acetobacter aceti are inoculated into a fermentation tank to perform primary fermentation to produce primary fermented material. In the second stage, yeast is added into the primary fermented material in a container to perform the secondary fermentation to produce secondary fermented material, and then the secondary fermented material is pasteurized to deactivate yeast, lactic acid bacteria and Acetobacter aceti in the container and stop fermentation reaction. Finally, the secondary fermented material is cooled to ambient temperature to prepare the kombucha fermented beverage preserving active fermentative bacteria and enzyme at ambient temperature. The invention is help to improve the preservation convenience of the kombucha fermented beverage and avoid excessive alcohol concentration.