Abstract:
A servo system includes multiple servo channels being driven by a common error signal. Each channel has a controller that receives an error signal and provides a drive signal to a driver. The servo channels are arranged serially, with a drive signal from one controller forming the error signal for a downstream controller. As a result, the downstream controller does not attempt to correct for phase error directly, but instead attempts to keep the upstream driver at or near its operational midpoint. The servo channels can be arranged in order of decreasing controller bandwidth, from fastest to slowest. In contrast with a parallel configuration, in which servo channels all simultaneously receive a common error signal, the serial configuration can allow each controller to use its full bandwidth, can eliminate crosstalk between servo channels, and can prevent saturation of upstream drive signals.
Abstract:
In one aspect, a frequency agile LADAR (laser detection and ranging) sensor includes a transmitter configured to provide laser pulses towards a target, a receiver configured to receive a reflected signal from the target and control circuitry configured to tune an optical frequency of a first laser pulse of the laser pulses to be different from an optical frequency of a second laser pulse of the laser pulses and tune an optical frequency of the receiver to be different than an optical frequency of a laser pulse most recently transmitted by the transmitter.
Abstract:
A servo system includes multiple servo channels being driven by a common error signal. Each channel has a controller that receives an error signal and provides a drive signal to a driver. The servo channels are arranged serially, with a drive signal from one controller forming the error signal for a downstream controller. As a result, the downstream controller does not attempt to correct for phase error directly, but instead attempts to keep the upstream driver at or near its operational midpoint. The servo channels can be arranged in order of decreasing controller bandwidth, from fastest to slowest. In contrast with a parallel configuration, in which servo channels all simultaneously receive a common error signal, the serial configuration can allow each controller to use its full bandwidth, can eliminate crosstalk between servo channels, and can prevent saturation of upstream drive signals.
Abstract:
In one aspect, a frequency agile LADAR (laser detection and ranging) sensor includes a transmitter configured to provide laser pulses towards a target, a receiver configured to receive a reflected signal from the target and control circuitry configured to tune an optical frequency of a first laser pulse of the laser pulses to be different from an optical frequency of a second laser pulse of the laser pulses and tune an optical frequency of the receiver to be different than an optical frequency of a laser pulse most recently transmitted by the transmitter.