Provided is a light emitting device. The hybrid power module includes a digitally controlled switching supply with an output coupled to an input of a digitally controlled linear voltage regulator. Here, the sensor cap has an outer diameter, which is smaller than or equal to an outer diameter of the gland, so that the sensor cap being welded to the gland beforehand can be fitted into the opening of the housing part. The total power of all tones for each symbol is obtained to produce a tone power quantity for each symbol.