New Observing Modes for the DBBC3

The DBBC3 was further enhanced by introducing\ua0new modes. Three different firmwares have\ua0recently been implemented for observing: Direct Sampling\ua0Conversion (DSC), arbitrary selection of bands\ua0(OCT), and Digital Down Conversion (DDC). These\ua0modes cover all the requirements of astronomical,\ua0VGOS, and legacy geodetic VLBI for the time being\ua0and the immediate future. In addition, the DBBC3\ua0offers unsurpassed compatibility to the relatively large\ua0number of other existing VLBI backends. A number\ua0of test observations were performed in the last months\ua0to achieve the best performance of the VGOS modes,\ua0and similar tests are planned for the EVN network. At\ua0the same time the DBBC3 is an important platform\ua0for additional new modes to be implemented for\ua0the BRAND receiver. Several DBBC3 systems are\ua0deployed in the field and more are under construction,\ua0with the number of 4-GHz bands ranging from two up\ua0to eight with resulting output data rates from 32 Gbps\ua0to 128 Gbps

DBBC3 Towards the BRAND EVN Receiver

The DBBC3 is a flexible VLBI backend and\ua0environment that supports a wide range of observational\ua0needs via a suite of FPGA firmware types. The\ua0hardware can sample up to eight 4 GHz-wide baseband\ua0signals and convert to digital streams over multiple\ua010GE links on fibre. The development team has an ongoing\ua0development programme that has enhanced existing\ua0modes and introduced new desired modes as user\ua0requirements evolve. Three dierent firmware types for\ua0observing have been implemented which will be briefly\ua0summarised: Direct Sampling Conversion (DSC), arbitrary\ua0selection of bands (OCT), Digital Down Conversion\ua0(DDC). These modes cover all the requirements\ua0of astronomical, VGOS and legacy geodetic VLBI of\ua0the present, but also of the near future. At the same\ua0time the DBBC3 is an important platform for additional\ua0new modes to be implemented for the BRAND\ua0receiver. This paper describes the use of the DBBC3\ua0for the receiver development, pointing out which element\ua0in the current DBBC3 structure will be part of\ua0the BRAND receiver in order to simplify its introduction\ua0into the existing VLBI environment at telescopes\ua0with a DBBC3 backend

First results from BRASS-p broadband searches for hidden photon dark matter

We discuss first results from hidden photon dark matter searches made with a prototype of the Broadband Radiometric Axion/ALPs Search Setup (BRASS-p) in the range of particle mass of 49.63-74.44 $\mu$eV (frequency range of 12-18 GHz). The conceptual design of BRASS and a detailed description of its present prototype, BRASS-p, are given, with a view of the potential application of such setups to hidden photon, axion, and axion-like particle (ALP) dark matter searches using heterodyne detectors in the range of particle mass from 40$\mu$eV to 4000$\mu$eV (10 GHz to 1 THz). Pioneering measurements made with BRASS-p achieve the record sensitivity of (0.3--1.0)$\times$$10^{-13}$ to the kinetic mixing between the normal and hidden photons, assuming the dark matter is made entirely of unpolarized hidden photons. Based on these results, a discussion of further prospects for dark matter searches using the BRASS-p apparatus is presented.Comment: 17 pages, 13 figures. Prepared for submission to JCA

DBBC VLBI2010

The Digital Base-Band Converters-2 (DBBC2) backend system has been adapted for supporting the VLBI2010 demands. The system architecture for this application is presented

DBBC2 Backend: Status and Development Plan

The Digital Base Band Converter-2 (DBBC2) system is in a mature phase now, and the deployment is continuing. A review of the backend is shown, and the new functionalities in development are reported

Design Aspects of the VLBI2010 System - Progress Report of the IVS VLBI2010 Committee

This report summarizes the progress made in developing the next generation VLBI system, dubbed the VLBI2010 system. The VLBI2010 Committee of the International VLBI Service for Geodesy and Astrometry (IVS) worked on the design aspects of the new system. The report covers Monte Carlo simulations showing the impact of the new operating modes on the final products. A section on system considerations describes the implications for the VLBI2010 system parameters by considering the new modes and system-related issues such as sensitivity, antenna slew rate, delay measurement error. RF1, frequency requirements, antenna deformation, and source structure corrections_ This is followed by a description of all major subsystems and recommendations for the network, station. and antenna. Then aspects of the feed, polarization processing. calibration, digital back end, and correlator subsystems are covered. A section is dedicated to the NASA. proof-of-concept demonstration. Finally, sections tm operational considerations, on risks and fallback options, and on the next steps complete the report