9IEC.IEC 444-1986 measurement of quartz crystal unit parameters by zero phase technique inπ-network,part I:basic method for the measurement of resonance frequency and resonance resistance of quartz crystal units by zero phase technique in aπ-network[S].[S.l.] :IEC,1986.
10COWLES John,GILBERT Barrie.Accurate gain/phase measurement at radio frequencies up to 2.5GHZ[J].Analog Dialogue,2001,35(5):2-4.