User-invoked calibration of modular system using an embedded calibration signal generator

摘要

A user obtains a set of modules, inserts them into slots of a chassis, and interconnects the modules to form a modular instrument. A signal path extends through the modules. To support calibration of the signal path, a first of the modules (or the chassis or a calibration module) includes a calibration signal generator. A computer directs the first module to apply the calibration signal from the generator to the signal path, and measures the power (or amplitude) of the output of the signal path. The computer reads a factory-measured value A of the calibration signal amplitude from a memory of the first module (or the chassis or the calibration module). The value A and the measured output power of the signal path are used to determine a gain of the signal path. The system compensates for that gain when the signal path is used to measure live operational signals.

主权项

1. A method for operating a computer in order to calibrate a signal transformation path that extends through a series of two or more interconnected modules, wherein an input to the signal transformation path resides in a first module of the series, wherein an output of the signal transformation path resides in a last module of the series, the method comprising:
(a) a computer sending a first instruction to the first module, wherein the instruction directs the first module to couple a calibration signal produced by a calibration signal generator to the input of the signal transformation path, wherein the calibration signal generator is located within the first module; (b) the computer reading measurement values from a memory of the first module, wherein the measurement values include a measured value of the amplitude of the calibration signal and a measured value of the frequency of the calibration signal; (c) the computer reading output power measurements from a power measuring device, wherein the output power measurements are measurements of power of an output signal produced at the output of the signal transformation path in response to said calibration signal being coupled to the input of the signal transformation path; (d) the computer calculating a gain between the input and the output of the signal transformation path based on the measured value of the amplitude of the calibration signal and based on the output power measurements; and (e) the computer storing the gain in a memory of the computer.