how to divide by two the number of points of a signal without losing

[pattousai]

Hi everybody.

Well, the question is pretty much what i already written in the title. How i divide by two the number of points of a IQ signal without losing his frequency?

Thanks for the attention and sorry for the bad english.

[Tomi Maila]

Please do not post your questions multiple times. For your question you should start learning elementary issues in signal processing. Take a look at Wikipedia article of sampling rate conversion.

[Ton Plomp]

QUOTE(pattousai @ May 18 2007, 10:21 PM)

Hi everybody.

Well, the question is pretty much what i already written in the title. How i divide by two the number of points of a IQ signal without losing his frequency?

Thanks for the attention and sorry for the bad english.

Hi Pattousai,

if you crosspost, please note us of the cross-posting and submit a link.

http://forums.ni.com/ni/board/message?board.id=170&message.id=248184#M248184' target="_blank">ni forums

Ton

[Jim Kring]

QUOTE(pattousai @ May 18 2007, 01:21 PM)

Well, the question is pretty much what i already written in the title. How i divide by two the number of points of a IQ signal without losing his frequency?

If you decimate (only keep every Nth point of) the y[] array of a waveform, then you will need to multiply the dT (time between points) by N. If you are using the Dynamic Data signal data type, then you can simply use the Sample Compression express VI. Search your palette for "Decimate" and you'll find some functions. One thing to be aware of is that you might want to do some averaging and not plain decimation -- the Sample Compression express VI has an averaging setting.