Software Support for Metrology
Software Downloads (SSfM)
Lock-In Amplifier Simulation Software: Release 2
A new version of the software is available for users who require the additional functionality we have added to the software. These additions include:
- Additional methods of defining simulated test signals, including defining signals in terms of their Fourier series.
- Random number generation using the Wichmann-Hill algorithm.
- Modelling noise using power law process and autoregressive processes. These are advanced options for users who have substantial digital signal processing knowledge.
Release 2 was developed using LabVIEW version 2009 and compiled into a standalone Windows executable.
As for Release 1, two versions of the software are provided, one for users who already have LabVIEW 2009 or the LabVIEW 2009 Run-Time Engine installed on their PC. This version is contained within the ZIP file lia_r2_excrte.zip.
A second version, lia_r2_incrte.zip, is for users who do not have a LabVIEW Run-Time Engine currently installed on their PC.
After you have downloaded and unzipped the file appropriate to your PC, follow the installation instructions to be found in the text file readme.txt.
Lock-In Amplifier Simulation Software: Release 1
The objective of the simulation software is to help answer questions about how well a lock-in amplifier can recover a signal from noise (the 'accuracy' of the result provided by the instrument) and about the possible dispersion of values obtained (the 'precision' of the result). The software allows users to investigate the performance and limitations of ideal and imperfect instruments applied to simulated and real test signals.
The software was developed using LabVIEW version 8.5 and compiled into a standalone Windows executable.
Two versions of the software are provided:
- One for users who already have LabVIEW or the LabVIEW 8.5 Run-Time Engine installed on their PC. This version is contained within the ZIP file lia_r1_excrte.zip.
- A second version, lia_r1_incrte.zip, is for users who do not have a LabVIEW Run-Time Engine currently installed on their PC.
After you have downloaded and unzipped the file appropriate to your PC, follow the installation instructions to be found in the text file readme.txt.
XGENLINE (8.1)
A sophisticated package for fitting curves to data and routines to use these curves, based round generalised polynomial regression fitting routines. It was developed at NPL in MatLab.
XLGENLINE (v1)
Excel software to find least-square polynomial of fit to data, given uncertainties in both X and Y.
Wichmann-Hill Random Number Generator
In 1982, the authors produced a pseudo-random number generator that has been widely used, but now has been shown to be inadequate by today’s standards. In producing a revised generator, extensive use has been made of a test package TestU01 for random number generators. Using this, criteria have been devised for the revised generator—also other high quality generators have been identified. Facilities have been devised to allow the new generator to be used in a highly parallel environment, which is likely to be a feature of many future applications.
EUnit
A test harness to implement unit testing for Excel. EUnit is specific to Excel and is implemented as part of Excel, so it can not be used with other spreadsheet packages. Therefore, unlike the rest of this guide, this appendix is only applicable to Excel and not to other spreadsheet packages.
NPLUnc
This software was developed at NPL to support the use of the Guide to the expression of uncertainty in measurement (GUM) and the first supporting document to the GUM, GUM Supplement 1, concerned with the use of a Monte Carlo method for uncertainty evaluation. The software enables users to apply the approaches to uncertainty evaluation described in these documents to the four example problems considered in GUM Supplement 1. The software is intended to allow users to reproduce the results presented in tables and figures contained within GUM Supplement 1, and to help users learn about the methods for uncertainty evaluation described in the GUM and GUM Supplement 1.
The software, which is downloaded as a zip file, takes the form of four application programs. Please start by reading the file readme.txt within that zip file.
NPLUnc (open source)
This software is intended to promote further the methods for uncertainty evaluation described in the GUM and GUM Supplement 1. Source code, written in the MATLAB programming language, is provided for applying the GUM uncertainty framework and a Monte Carlo method for uncertainty evaluation.
The software, which is downloaded as a zip file, takes the form of a set of html files and supporting files. Please start by reading the file readme.txt within that zip file. Users of MATLAB can use the MATLAB grabcode function to retrieve the M-code from these HTML files, and run the code directly.