时钟芯片Si5347在进行抖动性能测试时，测试抖动指标超过文档提供的指标值，请问这是什么原因?

Base/blank prototyping device:Quad PLL Jitter Attenuator:8-outputs up to 800 MHz

Low-Jitter, Quad DSPLL, 8-Output, Any Frequency (<712.5MHz), Any Output, Jitter Attenuator

"Factory pre-programmedQuad PLL Jitter Attenuator:8-outputs up to 800 MHz"

Quad DSPLL™ Jitter Attenuators

SI5347D-D、SI5347、SI5347D系列

Factory pre-programmed: Quad PLL Jitter Attenuator, 4-outputs up to 350 MHz.

64-Lead QFN

Low-Jitter, Quad DSPLL, 8-Output, Any Frequency (<712.5MHz), Any Output, Jitter Attenuator

Quad DSPLL™ Jitter Attenuators

SI5347D-D、SI5347、SI5347D系列

Factory pre-programmed: Quad PLL Jitter Attenuator, 4-outputs up to 350 MHz.

64-Lead QFN

Low-Jitter, Dual DSPLL, 4-Output, Any Frequency (<350MHz), Any Output, Jitter Attenuator

Low-Jitter, 4-Output, Any Frequency (<350MHz), Any Output, Jitter Attenuator

10-Channel, Any-Frequency, Any-Output Jitter Attenuator/ Clock Multiplier

SI5345A、SI5345系列

Base/blank prototyping device:Single PLL Jitter Attenuator:10-outputs up to 800 MHz;频点定制.时钟定制.可编程服务.频点烧录

64-QFN

Low-Jitter, 10-Output, Any-Frequency, Any-Output Clock Generator

SI5341B、SI5341系列

Base/blank prototyping device:频点定制.时钟定制.可编程服务.频点烧录

64-QFN

Low-Jitter, 4-Output, Any Frequency (<350MHz), Any Output, Jitter Attenuator

Dual/Quad DSPLL™ Jitter Attenuators

SI5346、SI5346A系列

Factory pre-programmedDUAL PLL Jitter Attenuator:4-outputs up to 800 MHz.频点定制.时钟定制.可编程服务.频点烧录

44-Lead QFN

10-Channel, Any-Frequency, Any-Output Jitter Attenuator/ Clock Multiplier

SI5345B、SI5345系列

Base/blank prototyping device:Single PLL Jitter Attenuator:10-outputs up to 350 MHz;频点定制.时钟定制.可编程服务.频点烧录

64-QFN

HIGH-FREQUENCY, ULTRA-LOW JITTER ATTENUATOR CLOCK WITH DIGITALLY-CONTROLLED OSCILLATOR

SI5344H、SI5344系列

Blank protoyping device: Coherent Optical Jitter Attenuator Clock 4-outputs <2.7GHz.频点定制.时钟定制.可编程服务.频点烧录

44-Lead QFN

Factory pre-programmed: Single PLL Jitter Attenuator: 2-outputs up to 350 MHz; Integer only synthesis

10-Output Low Jitter Any-Frequency Clock Generator

Si5341、Si5341B系列

Ultra low-jitter, 10-output, any frequency (< 350MHz), any output clock generator

64-QFN

si5341-d-evb

HIGH-FREQUENCY, ULTRA-LOW JITTER ATTENUATOR CLOCK WITH DIGITALLY-CONTROLLED OSCILLATOR

SI5342H、SI5342系列

Blank protoyping device: Coherent Optical Jitter Attenuator Clock 2-outputs <2.7GHz. 频点定制.时钟定制.可编程服务.频点烧录

44-Lead QFN

Low-Jitter, 4-Output, Any-Frequency, Any-Output Clock Generator

SI5340、SI5340A系列

Base/blank prototyping device:Clock Generator:4-outputs up to 800 MHz;Integer+Fractional synthesis 频点定制.时钟定制.可编程服务.频点烧录

44-QFN

Low-Jitter, 4-Output, Any-Frequency, Any-Output Clock Generator

SI5340、SI5340B系列

Factory pre-programmed: Clock Generator: 4-outputs up to 350 MHz; Integer+Fractional synthesis.

44-QFN

Factory pre-programmed:Single PLL Jitter Attenuator:4-outputs up to 350 MHz;

Low-Jitter,10-Output, Any-Frequency, Any-Output Clock Generator

SI5341B、SI5341系列

Base/blank prototyping device:频点定制.时钟定制.可编程服务.频点烧录

64-QFN

Factory pre-programmed:Clock Generator:4-outputs up to 350 MHz;

Base blank prototyping device: Clock Generator:10-outputs up to 350 MHz;Integer+Fractional synthesis

Base/blank prototyping device:Single PLL Jitter Attenuator:4-outputs up to 800 MHz;Integer+Fractional synthesis

Low-Jitter, 10-Output, Any Frequency (<1028MHz), Any Output, Jitter Attenuator

10-Channel, Any-Frequency, Any-Output Jitter Attenuator/ Clock Multiplier

SI5345A、SI5345系列

Base/blank prototyping device:Single PLL Jitter Attenuator:10-outputs up to 800 MHz;频点定制.时钟定制.可编程服务.频点烧录

64-QFN

Base/blank prototyping device:Single PLL Jitter Attenuator:2-outputs up to 800 MHz;

Factory pre-programmed:Clock Generator:10-outputs up to 350 MHz;Integer+Fractional synthesis

4-Output Low Phase Noise Jitter Attenuating Clock Generator

SI5344、SI5344B-D、SI5344B-Dxxxxx-GM系列

Factory pre-programmed: Single PLL Jitter Attenuator, 4-outputs up to 350 MHz, Integer+Fractional synthesis .

44-QFN

Base/blank prototyping device: