| 摘要 |
<p>The invention concerns digital-to-analogue converters for converting current. The converter includes a pair of differential branches with two transistors (T1, T2) controlled by a digital register (REG) activated at a clock frequency, and two resistive loads (R1, R2) receiving the currents of the differential branches to produce a differential electrical signal representing the analogue result of the conversion. The converter includes a dual switching of the currents of the differential branches: a first switching (Q1a, Q1b, Q2a, Q2b) authorises the transmission, to the loads, of the currents of the differential branches for 70 to 95% of the clock period and shunts these currents outside the loads the remainder of the time; a second switching (Q'1a, Q'1b, Q'2a, Q'2b) alternately and symmetrically makes a direct link followed by a cross link between the differential branches and the loads. The converter provides a signal with high spectral purity and can work with a good level of power in the four Nyquist zones of the spectrum of the output analogue signal, and in particular in the second and third zones.</p> |
