The LSTM is intended for applications requiring very accurate time interval measurements (LiDAR and Altimtrry systems, but not limited to). The measurement is performed by registering the moments of events corresponding to the start and stop signals of the time interval. Accuracy is achieved through the use of an interpolator, which generates an analog signal of a known shape at the time of an event and performs AD conversion of this signal. The analog waveform is determined during the calibration procedure.
The developed meter is designed as a universal measuring module, which can be included in various applications operating in space, and requiring measurement of time intervals with high accuracy and low dead time. Engineering Model of LSTM contains several systems of parametric stabilization, which allows maintaining high metrological characteristics in conditions of fluctuations in external temperatures from -40C ° to + 60C ° and radiation up to 100 Krad.
The Engineering Model of LSTM is small in size and low in power consumption and can be easily reconfigured for specific missions. Currently LSTM is used in HERA mission.
Main characteristics of BB2
Two measuring inputs A and B: LVDS levels
Minimum measurable time interval: 60 ns
Maximum measurable time interval: Tmax up to 167 ms
Precision – <10 ps (RMS)
Accuracy: depends on Tmax and the class of the internal clock generator used (for XO clock generator: Tmax X ± 50 ppm)
Communication interface: RS-422
External power supplies: + 3.3V, ± 5V
Power consumption: ≤4 W
Working temperature range: -40C ° ÷ + 60C °
Radiation level: up to 100Krad
Dimensions: 154×131.5 mm