| 摘要 |
<p>Amplification or generation of very low (and variable) frequency, low voltage, high current bipolar signals useful in electrical borehole telemetry systems is achieved using a duty cycle control device (32) for causing the alternate direct application of a positive voltage and a negative voltage to an integrator (30). A commutated clamp (36) is connected to the input of the integrator (30) for switchably connecting the integrator directly into a current loop with the load, connected to the output of the integrator, when neither voltage is being applied to the input of the integrator. <IMAGE></p> |
