| 摘要 |
<p>The process uses multiplication of vector angle and analysis of derivative to locate error. The procedure provides an estimation of the frequency error of a demodulator which is used to reconstruct two binary signals (I,Q) carried on two carriers of the same frequency but operating in phase quadrature. The procedure comprises the first stage of forming vectors having the successive pairs of values (I,Q) of two binary signals as components. The second stage includes applying to each vector a transformation which multiplies its angle by four, at least when it is equal to a multiple of /4, whilst retaining its modulus. The third stage includes calculating the average (x1,y1) of the transformed vectors. The frequency error is obtained as being equal to the angular derivative of the average vector.</p> |
