| 摘要 |
<p>A chart recorder is disclosed having a variable chart speed and a writing device in the form of a variable droplet rate ink jet pen. The signal pulses for ejecting ink droplets from the pen are generated by a voltage controlled oscillator, and circuits are provided to make the oscillator output frequency proportional to the chart speed, and also responsive to higher rates of pen movement, so that a substantially uniform density line is traced at all chart speeds and virtually all rates of pen movement. To simplify the circuit while maintaining an extremely wide range of writing speeds, the voltage sweep range of the oscillator is set at the upper end of the pen response frequency, and lower oscillator output rates are established by selectable R-C circuit components to match the speed of the chart recorder. To give more precision, a circuit embodiment is alos disclosed that generates pen control pulses proportional to the true rate of relative movement between the pen and the chart. The application of the latter circuit to an X-Y recorder is also disclosed.</p> |
