Pulsar Instruments

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==== The PSRIX2 System ==== For pulsar observations with the C+/K/Qu band receivers, the 4 or 8GHz outputs are processed using the wideband ADCs and the ROACH2 in 2GHz basebands. In addition the 7Beam signals can be processed by this system to generate a 512-channel full Stokes output down to 50μs. Refer to the figure below to get an overview of the system set up. {{ :pulsarinstruments:psrix2_overview.png?300|PSRIX2 Block Diagram}} {{ :pulsarinstruments:psrix2:r2_cropped.jpg?200| The ROACH2 board}} To handle a total of 8GHz bandwidth, the PSRIX2 system makes use of 4x ROACH2 boards, a gain control and an ADC calibration unit. All of these systems have their own RaspBerry Pi controls and can be accessed either as ''pulsar@asterix'' or as ''spobs@uptotrix'' machines. Details on controlling the ROACH2 clocks, and the ADC Cals are listed separately. * Choose the ADC CAL signal (100MHz signal based on the H-maser), noise output or modulated noise on the output of the calunit. * Choose between the CAL signal or the RF input using the ROACH2 Raspberry PI. Also use this interface to set the FPGA clocks in the ROACH2s. * Set the attenuation of the RF signal using [[:pulsarinstruments:psrix2:gain_atten_ctrl|this interface]].