Backends for old ABCD receivers (till mid March 2009)

Type

Channel Width

Bandwidth

Receiver (width mode)

Remark

1 MHz

Filterbank

1 MHz

4x256 MHz, 2x512 MHz, or, 1x1GHz

A100, B100 (narrow), A230, B230, C150, D150, C270, D270 (narrow or wide)

(1)

4 MHz

Filterbanks

4 MHz

9x1GHz

either HERA1 or HERA2 (wide), all other SIS receivers (wide) except 3mm

(2)

WILMA

Autocorrelator

2 MHz

18x930 MHz

HERA (wide)

(3)

VESPA

Autocorrelator

3.3 kHz-1.25 MHz

10-512 MHz

all SIS receives incl. HERA (narrow)

(4)

XPOL

VESPA

40kHz-1.25MHz

120-640MHz

A100 and B100 (narrow)

(5)

ABBA

(6)

In general, several backends can be attached to one receiver. Exceptions are listed below. The pako manual describes in detail how to configure the backends.

  1. 1MHz Filterbank: max. 4 parts; series, parallel, or mixed mode possible; using the 1MHz filterbank with 1GHz bandwidth excludes the use of VESPA with the same receiver. The filterbank can be shifted in multiples of 32MHz from the center frequency of the connected receiver.

  2. 4MHz Filterbank: max. 9 parts; use of the 4MHz filterbank excludes the use of VESPA on the same receiver. Frequency switching not available. While the channel spacing is 4MHz, the 3dB width is 5.4MHz and the noise equivalent width is 6.5 MHz

  3. WILMA: The Wideband Line Multiple Autocorrelator for HERA

  4. VESPA: The Versatile SPectrometer Array. Up to 18000 channels. In connection with HERA (9 pixels) the following combinations of resolution (kHz) and bandwidth (MHz) are possible: (20/40), (40,80), (80, 160), (320,320), (1250, 640); VESPA User Guide (2002), Summary in IRAM Newsletter No. 54 (Dec 2002), local contact: G. Paubert

  5. XPOL: Line and continuum polarimetry is possible at the 30m using a new type of IF polarimeter designated XPOL. The central feature of XPOL is the correlator VESPA where the IF signals from two orthogonally polarized receivers are cross correlated to determine the four Stokes parameters. A manual is in preparation, contact: C. Thum

  6. ABBA1 and ABBA2 (Adc Bolometer Backend) are the bolometer backends, i.e. dedicated PCs connected to the bolometers.

BackendsForAbcdReceivers (last edited 2009-04-16 08:26:25 by localhost)