Semi-digital programmable correlator, lab testing and - PowerPoint PPT Presentation

Semi-digital programmable correlator, � � � � � � lab testing and prototyping � At the University of Utah, we are working at the development of correlators and prototyping in the laboratory and on the sky with a pair of 3m telescopes. I will present the status of these efforts and our future plans. � � � * Lab setup with analog correlator � � � * Digital correlator � � � * Starbase � Stephan LeBohec, University of Utah � SIIWG Workshop, SLC, Friday January 30 th 2009 �

Table top test bench �

HV 700V � Function generator � Transformer � Transformer � 15Hz � 5v � Phase switch � Phase switch � Transformer � Transformer � Mixer � Lock-in amplifier (3Hz) � Computer �

Each measurement corresponds to 50 Each measurement corresponds to 50 readout of the locking amplifier with 3s readout of the locking amplifier with 3s averaging averaging �

Well, maybe not !! � Well, maybe not !! HV 700V � 500Ohm � 500Ohm � Function generator � Transformer � Transformer � 15Hz � 5v � Phase Phase switch � switch � x10 � x10 � Transformer � Transformer � Mixer � Lock-in amplifier (3Hz) � Computer �

Semi-digital Semi-digital Correlator Correlator � 200MHz digitization prototype � � � (1GHz Already possible) �

Semi-digital Semi-digital Correlator Correlator test test � 20MHz sine waves with relative phase 20MHz sine waves with relative phase �

StarBase StarBase: � Two 3m telescopes on a 23m baseline Two 3m telescopes on a 23m baseline � � � at Bonneville at Bonneville Seabase Seabase, Grantsville Utah , Grantsville Utah �

Possible observations from Possible observations from StarBase StarBase � S/N=A α n| n| γ | 2 ( Δ f.T/2) f.T/2) 1/2 1/2 � S/N=A A=7m2; A=7m2; α =0.3; =0.3; Δ f=100MHz =100MHz � n=5x10 =5x10 -5 -5 m -1 -1 s -1 -1 Hz Hz -1 -1 x2.5 x2.5 -m -m for S/N=5 for S/N=5 � 0.22mas � 0.53mas � 1.8mas � VERITAS
 Spica
 STARBASE


Possible observations from Possible observations from StarBase StarBase � S/N=A α n| n| γ | 2 ( Δ f.T/2) f.T/2) 1/2 1/2 � S/N=A A=7m2; A=7m2; α =0.3; =0.3; Δ f=100MHz =100MHz � n=5x10 =5x10 -5 -5 m -1 -1 s -1 -1 Hz Hz -1 -1 x2.5 x2.5 -m -m for S/N=5 for S/N=5 � Algol


Conclusions Conclusions � � * Lab tests progressing * Lab tests progressing � � * Semi-digital * Semi-digital correlator correlator � � � � � essentially working essentially working � � *StarBase StarBase telescopes tracking telescopes tracking � � � � � in Spring 2009 in Spring 2009 � � * Secondary optics and * Secondary optics and photodetectors photodetectors � � � � Summer 2009 Summer 2009 � � * Bring your toys to Utah * Bring your toys to Utah � � * * StarBase StarBase visit Saturday, visit Saturday, � � � � � meeting at 9:00 meeting at 9:00 � � � � � � � � at the Embassy Suites Hotel at the Embassy Suites Hotel ��

Evolution toward local digitization of the intensity Digital Asynchronous Transceiver (DAT) developed in Leeds for VERITAS