A system, a method and a built-in phase noise measurement apparatus are introduced. The built-in phase noise measurement apparatus includes a first DLL and a TDC, in which the first DLL circuit controls a delay of a first signal to generate a second signal based on a control code, tune the control code until a phase of the second signal is aligned to a phase of a reference clock signal, and record a value of the control code when the phase of the second signal is aligned to the phase of the reference clock signal. The DLL circuit controls the delay of the first signal based on the value of the control code after the phase of the second signal is aligned to the phase of the reference clock signal. The TDC determines the phase noise of the first signal based on the reference clock signal and the second signal.

A system, a method and a built-in phase noise measurement apparatus are introduced. The built-in phase noise measurement apparatus includes a first DLL and a TDC, in which the first DLL circuit controls a delay of a first signal to generate a second signal based on a control code, tune the control code until a phase of the second signal is aligned to a phase of a reference clock signal, and record a value of the control code when the phase of the second signal is aligned to the phase of the reference clock signal. The DLL circuit controls the delay of the first signal based on the value of the control code after the phase of the second signal is aligned to the phase of the reference clock signal. The TDC determines the phase noise of the first signal based on the reference clock signal and the second signal.

A time error vector is determined using pairs of two closest points of input-referred noise data that straddle respective crossing times indicating when a clock signal representation crosses a threshold value, a slew rate of the clock signal representation, and the crossing times. A system filter is applied to the time error vector in the frequency domain. A first RMS value is determined indicating a jitter value present in the filtered time error vector. A raw clock signal time error vector of the clock signal under test is generated, the system filter is applied to the raw clock signal time error vector in the frequency domain, and a second RMS value indicating a jitter content of the filtered raw clock signal time error vector is determined. The second RMS value is corrected using the first RMS value to thereby generate a jitter measurement compensated for input-referred noise.

A time error vector is determined using pairs of two closest points of input-referred noise data that straddle respective crossing times indicating when a clock signal representation crosses a threshold value, a slew rate of the clock signal representation, and the crossing times. A system filter is applied to the time error vector in the frequency domain. A first RMS value is determined indicating a jitter value present in the filtered time error vector. A raw clock signal time error vector of the clock signal under test is generated, the system filter is applied to the raw clock signal time error vector in the frequency domain, and a second RMS value indicating a jitter content of the filtered raw clock signal time error vector is determined. The second RMS value is corrected using the first RMS value to thereby generate a jitter measurement compensated for input-referred noise.

A control module for a lighting fixture may include an input circuit (e.g., a wireless communication circuit) that may be susceptible to noise generating by a noise-generating source (e.g., a lighting control device in the lighting fixture). The control circuit may execute a self-test procedure to determine if the magnitude of the noise is acceptable or unacceptable for normal operation of the control module. During the self-test procedure, the control circuit may measure a noise level at a connection of the input circuit and determine if the noise level causes the self-test procedure to fail. The control circuit may control the lighting load to multiple intensities, measure noise levels of the output signal at each intensity, and process the noise levels to determine if the test has passed or failed. The control circuit may illuminate a visual indicator to provide an indication that the self-test procedure has failed.

A control module for a lighting fixture may include an input circuit (e.g., a wireless communication circuit) that may be susceptible to noise generating by a noise-generating source (e.g., a lighting control device in the lighting fixture). The control circuit may execute a self-test procedure to determine if the magnitude of the noise is acceptable or unacceptable for normal operation of the control module. During the self-test procedure, the control circuit may measure a noise level at a connection of the input circuit and determine if the noise level causes the self-test procedure to fail. The control circuit may control the lighting load to multiple intensities, measure noise levels of the output signal at each intensity, and process the noise levels to determine if the test has passed or failed. The control circuit may illuminate a visual indicator to provide an indication that the self-test procedure has failed.

A jitter determination method for determining at least one jitter component of an input signal is described. The input signal is generated by a signal source. The jitter determination method includes: receiving the input signal; determining a step response based on the input signal, the step response being associated with at least the signal source; and determining at least one variation parameter associated with the determined step response, wherein the at least one variation parameter is indicative of a reliability of the determined step response. Further, a measurement instrument is described.

A jitter determination method for determining at least one jitter component of an input signal is described. The input signal is generated by a signal source. The jitter determination method includes: receiving the input signal; determining a step response based on the input signal, the step response being associated with at least the signal source; and determining at least one variation parameter associated with the determined step response, wherein the at least one variation parameter is indicative of a reliability of the determined step response. Further, a measurement instrument is described.

A measuring device facilitates equipment calibration. A measuring device for measuring noise contained in equipment having a prescribed resistance value is provided with a first voltage-dividing circuit connected to a direct-current power source, a second voltage-dividing circuit connected in parallel with the first voltage-dividing circuit , and a measuring unit which measures a first voltage-divided voltage output from the first voltage-dividing circuit, and a second voltage-divided voltage output from the second voltage-dividing circuit, a calculating unit which calculates the difference between the measured first voltage-divided voltage and second voltage-divided voltage, and an output unit which outputs the calculated result, wherein: the first voltage-dividing circuit outputs the first voltage-divided voltage from the equipment and a first resistor, connected in series.

A measuring device facilitates equipment calibration. A measuring device for measuring noise contained in equipment having a prescribed resistance value is provided with a first voltage-dividing circuit connected to a direct-current power source, a second voltage-dividing circuit connected in parallel with the first voltage-dividing circuit , and a measuring unit which measures a first voltage-divided voltage output from the first voltage-dividing circuit, and a second voltage-divided voltage output from the second voltage-dividing circuit, a calculating unit which calculates the difference between the measured first voltage-divided voltage and second voltage-divided voltage, and an output unit which outputs the calculated result, wherein: the first voltage-dividing circuit outputs the first voltage-divided voltage from the equipment and a first resistor, connected in series.