DIGITAL AMPLITUDE MODULATOR AND CONTROL METHOD FOR DIGITAL AMPLITUDE MODULATOR

摘要

According to one embodiment, a digital amplitude modulator includes a power supply unit, a measurement unit, a calculation unit, and a power controller. The power supply unit supplies a power supply voltage to a plurality of power amplifiers. The measurement unit measures the output power and reflection coefficient of a synthesizer. The calculation unit calculates loss power occurring in each power amplifier in an ON state, and reflected power consumed by each power amplifier in the ON state. The power controller controls all the power amplifiers to be in an OFF state, and performs a normal operation, and controls the input voltage of the power supply unit or ON/OFF of the plurality of power amplifiers.

主权项

1. A digital amplitude modulator comprising:
normal number of power amplifiers as at least some of a plurality of power amplifiers configured to amplify a power of a transmission signal, being juxtaposed and ON/OFF-controllable according to a voltage amplitude level of the transmission signal to be modulated; a synthesizer configured to synthesize outputs of the respective power amplifiers to generate an amplitude modulation wave, and to send the generated amplitude modulation wave to a predetermined broadcasting service area; a power supply unit configured to supply a power supply voltage to the plurality of power amplifiers; a measurement unit configured to measure output power and a reflection coefficient of the synthesizer; a calculation unit configured to calculate, based on the output power and the reflection coefficient that is measured by the measurement unit, and information of input power supplied by the power supply unit, loss power occurring in each power amplifier in an ON state and reflected power consumed by each power amplifier in the ON state, and a power controller configured to:
control all the power amplifiers to be in an OFF state when a sum of the loss power and the reflected power that is calculated by the calculation unit is higher than a first threshold which is an upper limit of a tolerance range;perform a normal operation of setting the normal number of power amplifiers in the ON state when the sum is lower than a second threshold which is a lower limit of the tolerance range;compare the output power with normal rated power defined by digital broadcasting when the sum of the loss power and the reflected power falls within a range from the second threshold (inclusive) to the first threshold (inclusive); andcontrol an input voltage of the power supply unit or ON/OFF of the plurality of power amplifiers to perform a power increasing operation of increasing the output power obtained at the time of the normal operation or a power decreasing operation of decreasing the output power obtained at the time of the normal operation, based on the comparison result.