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Receivers

All antennas are equipped with dual polarization receivers for the 3mm, 2mm, and 1.3mm atmospheric windows. The frequency range is 80GHz to 116GHz for the 3mm band, 129GHz to 174GHz at 2mm, and 201GHz to 267GHz for the 1.3mm band.

Each frequency band of the receivers is dual-polarization with the two RF channels observing at the same sky frequency. The mixers are single-sideband, with a typical image rejection of 10dB. Only one frequency band (dual polarization) can be connected to the IF transmission lines at any time. Because of this reason and due to pointing offsets between different frequency bands, only one band can be observed at any time. One of the other bands is in stand-by (power on and local oscillator phase-locked) and is available, e.g., for pointing and focusing. Time-shared observations between frequency bands is possible, though not very efficient.

The two IF-channels (one per polarization), each 4GHz wide, are transmitted by optical fibers to the central building. The new wide-band correlator WideX is able to process both 4GHz wide IFs simultaneously with a fixed spectral resolution of about 2MHz. The narrow-band correlator, on the other hand, can process the 4GHz bandwidth only partially, but with spectral resolution up to 39kHz. A dedicated IF processor converts selected 1GHz wide slices of the 4-8GHz first IFs down to 0.1-1.1GHz, the input range of the narrow-band correlator. Further details are given in Section [*].


Table: PdBI receiver specifications. The tuning ranges refer to a centering of the respective sky frequency at the center of the IF band at 6GHz
  Band 1 Band 2 Band 3
RF coverage 80-116 129-174 201-267
$\rm T_{rec}$ LSB 40-55 30-50 40-60
$\rm T_{rec}$ USB 40-55 40-80 50-70
$\rm G_{im}$ -10dB -12 -10dB -12 -8dB
RF range LSB 80-104 129-168 201-264
RF range USB 104-116 147-174 264-267


next up previous contents index
Next: Wideband correlator Up: Capabilities Previous: Spatial Resolution   Contents   Index
Gildas manager 2011-09-07