摘要:
A frequency conversion section (2, 3) sweeps an object signal within a desired measurement frequency range, thereby frequency-converting the object signal. A peak detector (6) detects a peak of an output from the frequency converting section (2, 3). A measurement detector (7) measures and detects the output from the frequency conversion section (2, 3) simultaneously with the peak detection by the peak detector. The measurement detector (7) has an output characteristic lower than an output characteristic of the peak detector. A display (12) displays an output from the peak detector (6) and an output from the measurement detector (7) on a single display screen, in synchronism with the sweeping by the frequency conversion section (2, 3), with these outputs of the peak detector (6) and the measurement detector (7) being plotted along an axis representative of frequencies. In another mode of the invention, an alarm device indicates the fact that an output from the peak detector has exceeded a predetermined allowable limit level.
摘要:
An input processing section (1 - 7) outputs a digital signal corresponding to a frequency sweep range of an input signal. A memory (8) stores the digital signal. A display (9) displays the digital signal stored in the memory (8) as an image which is developed along a frequency axis. A scroll command section (20) provides a command for shifting the image. A controller (10) supplies, to the input processing section (1 - 7), a first control signal for causing the input processing section (1 - 7) to process the input signal in a first frequency sweep range and supplies, to the memory (8), a second control signal for causing the memory (8) to store the digital signal, prior to reception of the command. When the command is received, the controller (10) supplies, to the input processing section (1 - 7), a third control signal for causing the input processing section (1 - 7) to process the input signal in a second frequency sweep range in accordance with a content of the command and supplies to the memory (8), a fourth control signal for causing the memory (8) to store the digital signal. The display (9) displays an image of the second frequency sweep range to be continuous with the image of the first frequency sweep range which is shifted in accordance with the command.
摘要:
Disclosed is a test and measurement instrument (200) having a multiple variable bandwidth frequency mask. The instrument includes an input processor (205, 210, 220) for receiving an input signal and producing a digital signal, as well as a trigger signal generator (260, 262) for generating a trigger signal on the occurrence of a trigger event. A time to frequency converter (250, 252) converts a frame of digital data from the digital signal into a frequency spectrum having at least two frequency bins of dissimilar frequency widths. Each frequency bin has a power amplitude value. The trigger signal is generated when the power amplitude value of any of the at least two frequency bins violates an associated reference power level. In some cases the output may be shown as a density trace, and the trigger signal generated when any point of the density trace violates an associated density threshold.
摘要:
To produce data of an initial analysis range and a range zooming a part of it while updating them in parallel. A first frequency analysis range and a second frequency analysis range that is narrower than the first one are set with an operation panel 34, etc. A first signal path 171 produces first time domain data of a frequency converted signal under test according to a first data production rate that is set depending on the first frequency analysis range. A second signal path 172 produces second time domain data of frequency converted signal under test according to a second data production rate that is set depending on the second frequency analysis range and is slower than the first data production rate. A CPU receives the first and second time domain data in parallel and produces first and second frequency domain data by fast Fourier transform wherein frequency shift amounts in the frequency conversions in the first and second signal path are different depending on a difference between the center frequencies of the first and second frequency analysis ranges.
摘要:
The invention relates to a method for identifying a material, which comprises the following steps: measuring (200) a spectrum of electromagnetic radiation transmitted through the material to be identified; determining (202, 204) at least one energy band, referred to as a measurement band, and spectral coefficients of a comparison function in said measurement band, from the measured spectrum; estimating (PH1, PH2), using predetermined spectral coefficients, the nature and/or thickness of the material to be identified on the basis of a set of reference spectral parameters relating to reference thicknesses and/or materials and defined within reference bands. The estimation comprises at least the two following steps: previously selecting (208i, 208p) a plurality of reference thicknesses and/or materials, referred to as possible candidates, from a comparison of the spectral coefficients determined with at least one portion of the reference spectral parameters; and estimating (222) the nature and/or thickness of the material to be identified, from a comparison of the spectral coefficients determined with the spectral parameters of at least one portion of the possible candidates, in at least one energy band that is common to the reference bands of said at least one portion of the possible candidates and the measurement band.
摘要:
A test and measurement instrument (200) which automatically detects excessive in-band but out-of-span energy (205) and notifies the user of the condition.
摘要:
A test and measurement instrument converts digital data that represents an input signal into a series of frequency spectra and accumulates frequency spectra into a bitmap database in response to a gating signal. In some embodiments, the gating signal is generated when the instantaneous power of the input signal violates a power threshold.