Calibration method of modulation power for DVB-H test apparatus

摘要

This invention relates to a calibration method of modulation power for DVB-H test apparatus for reducing the calibration time for the power loss in the RF cable to half through calibration using the expected power loss of the modulated wave at an arbitrary frequency based on the measured power losses of the continuous wave over frequencies in the RF cable. The calibration method of modulation power for DVB-H test apparatus that is performed by the computer with installed calibration program therein and connected to the power meter of the DVB-H test apparatus, comprises and includes the steps of: commanding DVB-H test apparatus to output continuous waves having frequencies from the start frequency to the stop frequency with increment of frequency step in accordance with the preset power level; storing CW power offset, that is the difference between the actual power level and the preset power level, to the table after receiving actual power level of continuous waves having frequencies from the start frequency to the stop frequency with increment of frequency step from the power meter; commanding DVB-H test apparatus to output a modulated wave that carries data on a continuous wave having an arbitrary frequency between the start frequency and the stop frequency, thereafter receiving actual output power level from the power meter, and calculating the modulation power offset between the continuous wave and the modulated wave at the corresponding arbitrary frequency, thereafter commanding DVB-H test apparatus to output the preset power level added with the power offset of the continuous wave and the power offset of the modulated wave when transmitting the modulated wave.

主权项

1. A calibration method of modulation power for a DVB-H (Digital Video Broadcasting-Handheld) test apparatus performed by a computer having a calibration program installed therein and connected to a power meter of the DVB-H test apparatus, comprising:
(a) commanding the DVB-H test apparatus to output continuous waves having frequencies from a start frequency to a stop frequency, wherein each interval between adjacent frequencies is equal to a frequency step, the continuous waves having a preset power level; (b) receiving an actual power level of each of the continuous waves from the power meter, obtaining a continuous wave power offset which is a difference between the actual power level and the preset power level, and storing the continuous wave power offset in a power offset table; and (c) commanding the DVB-H test apparatus to output modulated waves, each of which carries data on a continuous wave having a frequency within a range from the start frequency to the stop frequency, receiving an actual output power level of each of the modulated waves from the power meter, obtaining the modulation power offset between the continuous wave and the modulated wave at each frequency among the frequencies from the start frequency to the stop frequency, and thereafter commanding the DVB-H test apparatus to output each modulated wave whose power level is equal to a total power level obtained by adding the preset power level, the continuous wave power offset stored in the power offset table and the modulation power offset so as to obtain an expected power loss at a cable for each modulated wave based on an actual power loss at the cable for each continuous wave wherein the cable is connected between the DVB-H test apparatus and an RF (radio frequency) connector.