From 390590f48f2add59e8a89c621050ed63c367c2e1 Mon Sep 17 00:00:00 2001 From: Martin Fouilleul Date: Tue, 19 Jul 2022 12:01:19 +0200 Subject: [PATCH] Edits in the NTP section to address Hayden's notes --- selected/time.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/selected/time.md b/selected/time.md index 6ca6545..6e2b4cf 100644 --- a/selected/time.md +++ b/selected/time.md @@ -211,10 +211,10 @@ Links: [Mills, Analysis and Simulation of the NTP On-Wire Protocols](https://www The clock filter is a shift register containing the last 8 samples produced by the on-wire protocol. The filter algorithm selects the sample with maximum expected accuracy. It is based on the observations that: -* The samples with the low [NOTE(hayden): is this meant to read 'lowest'?] network delay were likely to exhibit a low error at the time they were produced. +* The samples with the lowest network delay were likely to exhibit a low error at the time they were produced. * Older samples carry more accuracy than newer ones due to clock drift. -As a new sample is pushed to the register, it evicts the oldest sample. The dispersion values of the other samples are then incremented by $\varphi_c\times\Delta_t$, where $\Delta_t$ is the time elapsed since the last update from the server. A distance metric $\lambda_i$ is affected [NOTE(hayden): as in appended?] to each sample: +As a new sample is pushed to the register, it evicts the oldest sample. The dispersion values of the other samples are then incremented by $\varphi_c\times\Delta_t$, where $\Delta_t$ is the time elapsed since the last update from the server. A distance metric $\lambda_i$ is associated to each sample: $\lambda_i = \frac{\delta_i}{2}+\varepsilon_i \,.$ @@ -224,7 +224,7 @@ The peer's dispersion $\varepsilon_p$ is computed as an exponentially weighted a $\varepsilon_p = \sum_{i=0}^{N-1}\frac{\varepsilon_i}{2^{(i+1)}} \,.$ -The server's jitter $\psi_p$ is computed as the root mean square (RMS) of the offsets differences with respect to the offset of the first sample's in the list [NOTE(hayden): This sentence is difficult to read -- it may be because of the multiple forms of gramatical possessiveness. There also might be some typos in that regard]: +The server's jitter $\psi_p$ is computed as the root mean square (RMS) of the offsets differences with respect to the offset of the first sample's in the list [NOTE(hayden): This sentence is difficult to read -- it may be because of the multiple forms of gramatical possessiveness. There also might be some typos in that regard][NOTE(martin): let me know if this one works better: The server's jitter $\psi_p$ is computed as the root mean square (RMS) of the differences of each offset with the first offset in the list]: $\psi_p = \frac{1}{n-1}\sqrt{\sum_{i=0}^{N-1}(\theta_0-\theta_i)^2} \,.$