Fast Fourier Transform Spectrometer (FFTS)

Configuration

The FFTS contains two individual units which can be connected to one or two receivers through the IF processor. Both units have a bandwidth of 1 GHz, thus providing either 1 GHz bandwidth for two receivers simultaneously or 2 GHz bandwidth for one receiver. However, care must be taken with the outermost 30 MHz of each FFTS unit since that part will be affected by cutoff effects by the internal FFTS filters. Also aliasing effects may occur in the outermost parts. Hence, in practice it is recommended to ensure an overlap by at least 100 MHz of the two FFTS units leading to a useable full bandwidth of 2.0 - 0.1 - 2*0.03 = 1.84 GHz.

Instrument	Bandwidth	No of channels	Channel separation [kHz]
FFTS	1 GHz	1024	976.56
		2048	488.28
		4096	244.14
		8192	122.07