A Signal Frequency Measurement Method Based on Two DFT Complex Spectral Lines
A technology of signal frequency and measurement method, applied in the direction of frequency measurement device, etc., can solve problems such as large amount of calculation
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Embodiment 1
[0049] The specific steps are as follows:
[0050] Step (1): Sampling rate Fs=1500Hz, continuously intercepting signal x(n) of N=512 points, performing windowing processing to obtain windowing signal y(n), the formula of windowing processing is:
[0051] y(n)=x(n)·w(n),
[0052] Among them, w(n) selects the Hanning window function sequence of N=512 points, namely:
[0053]
[0054] Step (2): Carry out discrete Fourier DFT transform to windowed signal y (n), obtain discrete frequency spectrum Y (k), wherein discrete frequency serial number k=0:(N-1);
[0055] Step (3): In the range of discrete frequency numbers [15, 23], that is, within the range of corresponding frequencies [43.945, 67.383] Hz, search for the largest spectral line of |Y(k)| as the highest spectral line, and compare the largest spectral line Spectral lines on both sides |Y(k)| value, select the largest spectral line as the second highest spectral line, and record the discrete frequency number k of the two ...
Embodiment 2
[0065] Step (1): Sampling rate Fs=1500Hz, continuously intercepting signal x(n) of N=512 points, performing windowing processing to obtain windowing signal y(n), the formula of windowing processing is:
[0066] y(n)=x(n)·w(n),
[0067] Among them, w(n) selects the Blackman (BlackMan) window function sequence of N=512 points, namely:
[0068]
[0069] Step (2): Carry out discrete Fourier DFT transform to windowed signal y (n), obtain discrete frequency spectrum Y (k), wherein discrete frequency serial number k=0:(N-1);
[0070] Step (3): In the discrete frequency range [15,23], that is, within the range of the corresponding frequency [43.945,67.383]Hz, search for (|Re(Y(k))|+|Im(Y(k))| ) as the highest spectral line, and compare the (|Re(Y(k))|+|Im(Y(k))|) values of the spectral lines on both sides of the largest spectral line, and select the largest spectral line as Sub-high spectral line, record the discrete frequency number k of the two spectral lines 1 and k 2 =k ...
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