| US 7,564,897 B2 | ||
| Jitter measuring apparatus, jitter measuring method and PLL circuit | ||
| Kiyotaka Ichiyama, Tokyo (Japan); Masahiro Ishida, Tokyo (Japan); Takahiro Yamaguchi, Tokyo (Japan); and Mani Soma, Seattle, Wash. (US) | ||
| Assigned to Advantest Corporation, Tokyo (Japan) | ||
| Filed on Jul. 22, 2004, as Appl. No. 10/896,751. | ||
| Prior Publication US 2006/0018418 A1, Jan. 26, 2006 | ||
| Int. Cl. H04B 3/46 (2006.01) | ||
| U.S. Cl. 375—226 [375/224; 375/376] | 15 Claims |
| 1. A jitter measurement apparatus for measuring an intrinsic jitter of a circuit to be tested including a phase detector which
outputs a signal according to a phase difference between a supplied first input signal and a supplied second input signal,
comprising:
an input unit for supplying an identical signal to said phase detector as the first input signal and as the second input signal;
and
a jitter measurement unit for measuring the intrinsic jitter which is generated in an inside of the circuit to be tested by
measuring a jitter of a signal which is generated in an inside of the circuit to be tested according to a signal output from
said phase detector,
wherein the intrinsic jitter is measured in a state of no jitter derived from the input signals being included in the output
signal of the phase detector by supplying the identical signal as the first input signal and as the second input signals,
wherein the circuit to be tested comprises a latter circuit which receives a signal output from said phase detector and outputs
a signal based on a received signal,
wherein said jitter measurement apparatus measures a jitter of a signal output from said latter circuit, and
wherein said jitter measurement unit measures an intrinsic jitter of said latter circuit based on a difference between a jitter
of a signal output from said phase detector and a jitter of a signal output from said latter circuit.
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