Current WAPP Capabilities

I. Single Pixel Spectral Line

1. 195kHz to 50MHz Bandwidth
   • 1 polarization, 3-level autocorrelation: 16384 spectral channels
   • 2 polarizations, 3-level autocorrelation: 8192 spectral channels
   • 1 polarization, 9-level autocorrelation: 4096 spectral channels
   • 2 polarizations, 9-level autocorrelation: 2048 spectral channels
   • Full Stokes, 3-level autocorrelation: 8192 spectral channels
   • Full Stokes, 9-level autocorrelation: 2048 spectral channels
2. 100MHz Bandwidth
   • 1 polarization, 3-level autocorrelation: 8192 spectral channels
   • 2 polarizations, 3-level autocorrelation: 4096 spectral channels
   • 1 polarization, 9-level autocorrelation: 2048 spectral channels
   • 2 polarizations, 9-level autocorrelation: 1024 spectral channels
   • Full Stokes, 3-level autocorrelation: 2048 spectral channels

II. ALFA Spectral Line

1. 195kHz to 50MHz Bandwidth
   • 2 polarizations, 3-level autocorrelation: 8192 spectral channels
   • 2 polarizations, 9-level autocorrelation: 2048 spectral channels
   • Full Stokes, 3-level autocorrelation: 4096 spectral channels
   • Full Stokes, 9-level autocorrelation: 1024 spectral channels
2. 100MHz Bandwidth
   • 2 polarizations, 3-level autocorrelation: 4096 spectral channels
   • Full Stokes, 3-level autocorrelation: 2048 spectral channels

Note The WAPPs always deliver their maximum number of spectral channels, this cannot be set to a lower number.

Note 9-level autocorrelation achieves 96% of the signal-to-noise of analog correlation; 3-level autocorrelation achieves 81%.

III. Pulsar Modes

• 50MBytes/s max for correlator board
• >50MBytes/s max for EDT/computer
• 38MByte/s max data rate to disk

The best resolution for a 100MHz bandwidth, using 16 bits/lag, and summing the polarizations is given by the formulae:

     #lags = (i - 1)* 6.25,  where i = integration time in usecs
     Data rate to disk = 12MBytes/s;  Resolution = 100MHz/#lags

Integration time	Max lags	Resolution
100µs	616	162kHz
64µs	392	255kHz
32µs	192	520kHz

Direct Sampling

2 channels,continuous sampling

Bandwidth(MHz)	Data Rate (Mb/s)	Bit Packing
50	25	1
25	25	2
12.5	25	4
6.25	12.5	4
3.125	6.25	4
1.56	3.12	4
0.78	1.56	4
0.390	0.78	4
0.195	0.39	4