| 摘要 |
PROBLEM TO BE SOLVED: To provide a direct digital radio frequency modulator.SOLUTION: The present invention relates to a direct digital radio frequency modulator 10 comprising a plurality of input terminals IN1 to INn arranged for being fed with a multi-bit digital signal, and a plurality of converter circuits CC1 to CCn, each converter circuit being arranged for receiving at an input terminal one bit of the multi-bit digital signal and for outputting at converter circuit output terminals OUT1 to OUTn an analog signal in accordance to the bit, each converter circuit comprising an input transistor arranged for receiving the one bit for enabling the converter circuit to produce the analog signal, a current source transistor, and a frequency modulator output terminal 12 connected to the output terminal of each converter circuit for providing an analog output signal A, characterized in that the converter circuit further comprises an additional transistor in cascade to the current source transistor.SELECTED DRAWING: Figure 3 |
