Phase Shift and Power Spectrum..

[gokul_bits]

I am implementing a Lock-in amplifier.. the signal tht i am talking abt comes from the multiplier which does the analog multiplication of the input signal and the reference signal.. so when i pass tht into the amplitude spectrum and then use the extract signal vi, i can specify that i need only the value at point - '0'.. and thus i can take tht value as the reading right.. suppose if i use the filter-rolling average method, i am quite confused abt choosing the correct type of filter (how do we decide tht) and also the implementation of rolling-average.. can u just gimme me a link tht explains rolling-average and also tell me a how is it useful in this case...

thnx..

gokul.

[gokul_bits]

some one plz help me...

[gokul_bits]

plz.. help me... plz..

[PhillipBrooks]

Try searching the forums for your question!

Rolling Average

http://forums.ni.com/ni/board/message?board.id=170&message.id=165594&query.id=103851#M165594

Some of the people answering your previsous questions have helped in this thread...

[Mark H]

Hi Gokul,

Probably the easiest way to measure the DC value of a sampled signal is to use the "AC & DC Estimator (Not in Base Package)" VI, which is found in the Analyse>Signal Processing>Time Domain functions palette.

The function also estimates the "total AC (RMS)" value of the signal.

Try to ensure that you sample several cycles at least (ideally 6 or 7 or more) of any periodic frequency content to minimise measurement/separation error.

Mark H.