ddc bw How many?

[alipio]

Hello
Some questions about pxi rf 5660
1-When using RF5660 in DDC mode, how many bandwidths can be set to extract I+Q signals?
2- maximun data transfer speed using pxi controller to internal controller disk and using scsi interface.
3- benchmarks of spectrum seewp speed if available.

Thanks

Alipio

[Dustin_W]

Alipio-

1) There are 8 discrete bandwidths available:
1.25MHz
800kHz
400kHz
200kHz
100kHz
50kHz
25kHz
12.5kHz

When you select a bandwidth the board will go to the next highest value. If you select something above 1.25MHz, you will acquire with the maximum 20MHz bandwidth.

2) The maximum transfer speed is determined by the PXI bus limitations. The PXI bus is identical to the PCI bus in your desktop computer. The maximum burst rate is ~133 MB/s, sustained is closer to 80MB/s.

3) There are too many variables to effectiviely do benchmarks for spectrum sweeps, so unfortunately, none are available.

I hope this helps-

Dustin

[alipio]

Thanks Dustin.
That is what I wanted to Know.

Regarding point 3, what I meant is time to change downconveter frequency and to settle down conditions before adquiring data. That time is supposed to be some miliseconds and that will affect broad band sweep time. You have some idea about that?

Alipio

[Brent_R]

Hello Alipio,

The tuning speed will depend on two factors, your required frequency accuracy and the step size between consecutive center frequencies. We provide three data points in the PXI-5660 specifications to provide some insight into the tuning performance of the instrument.

1% of step size..... 10 ms max
0.01% of step size.. 20 ms max
1 ppm of step size.. 30 ms max

Please see the PXI-5660 specifications for more detail.

http://www.ni.com/pdf/products/us/4mi469-471.pdf

Regards,

Brent R
Applications Engineer
National Instruments

[alipio]

Hello Brent.

Thanks a lot for the info.

Alipio.