公开(公告)号：JPH07104017A

公开(公告)日：1995-04-21

申请号：JP27308693

申请日：1993-10-05

Applicant: ADVANTEST CORP

Inventor： SAKIYAMA SHIN ,  HASEGAWA TORU ,  OSAWA KATSURO

IPC: G01R27/26 ,  G01R27/28 ,  G01R29/22 ,  G01R31/00

Abstract: PURPOSE:To correct an error due to the residual capacity, and to perform the accurate measurement at the time of measuring of the load capacity characteristic in a device for inspecting characteristic of a quartz oscillator. CONSTITUTION:A DUT unit 11, which includes a residual capacity 13, and a load capacity unit 12 are 4-terminal-displayed, and about a ratio alpha of the input/output voltage at the time of resonance, a alpha value alphas in the case where the DUT unit 11 is shorted and the loading capacity unit 12 is shorted is really measured. An alpha value alpha2 in the case where the DUT unit 11 is loaded with a constant known quantity and the load capacity unit 12 is short-circuited is really measured. An alpha value alphas' in the case where the DUT unit 11 is short- circuited and the load capacity unit 12 is loaded with a constant known quantity is really measured. The DUT unit 11 is opened, and the impedance Z0 is computed. The DUT unit 11 is short-circuited, and the impedance Zs is computed. The residual capacity 13 is decided by obtaining an integral between the real measured value and an operation expression. True resonance frequency after the correction is obtained.

公开(公告)号：JPH10200403A

公开(公告)日：1998-07-31

申请号：JP34697

申请日：1997-01-06

Applicant: ADVANTEST CORP

Inventor： OSAWA KATSURO ,  WAKAMOTO SATORU

IPC: H03B28/00 ,  H03L7/16

Abstract: PROBLEM TO BE SOLVED: To make an S/N high and to make a separating shield and an amplifier simple and inexpensive. SOLUTION: A variable frequency divider 12 undergoes frequency dividing of an output of a VCO 31; a frequency converter 33 converts the output into a low frequency with an output of a direct digital synthesizer 32; a comparator 13 performs phase comparison of the frequency conversion output with a reference signal of a reference oscillator 14; and the comparison output is supplied to the VCO 31 through a loop filter 15 to control the VCO 31. For instance, 30 to 100MHz signal outputs an oscillation output of the VCO 31 to an output terminal 24 through a switch 34, and 100kHz to 30MHz signal outputs from the DDS 32 to the terminal 24.