Crosstalk measurement

Crosstalk can be complicated depending on the dominant crosstalk path within the ROIC. Crosstalk between the ROIC subcircuits and routing to the detector can also occur. For this reason, any crosstalk testing at the ROIC level should be repeated at the SCA level. Typically, crosstalk measurements are made optically and thus require a detector. 

Data Acquisition In theory, the acquisition is simple focus the smallest possible spot on one detector and measure the signal from that detector and the signal Sj from a few surrounding detectors. In practice, reliable crosstalk measurements are difficult. As mentioned elsewhere, it is difficult to know when the spot is well focused and when it is centered on a particular detector. It is helpful to have automated systems that allow us to acquire data in a methodical way for many scans as a function of position X, y on the array for many lens-to-detector distances. We can then select from that data those that yield the sharpest off-to-on transitions and minimum crosstalk. 

Uncertainty The relative uncertainty for crosstalk measurements is large. The effect of a nonzero spot size may be comparable to the allowed crosstalk, so the way in which we account for the spot size is critical, and may make the difference in meeting or failing the specification. When combined with the uncertainty in finding the best focus, the entire process is very frustrating unless it is approached from the beginning with an appreciation of the difficulties and a careful plan to overcome them. 

The relationship of the dielectric constant of the cable insulation to crosstalk can be measured by testing two cables for crosstalk with the same dimension, but different insulation materials. The cable with the lower dielectric constant has less capacitance unbalance, thus resulting in lower crosstalk than the cable with the higher dielectric constant. 

In applications where numerous compressors are in close proximity, an additional measurement point on the base is useful for identifying structural resonance or crosstalk between the units. 

Figure 16. The variation (crosstalk) of modulation index with filter bandwidth, when the measurement cell contains a high concentration (0.05 Bar partial pressure) of H20 vapour impurity (both cells are 1 m in length cell at 1 Bar and 20 °C, and the reference cell contains 100% C02 gas).

N. Okui and E. Okada. Wavelength dependence of crosstalk in dual-wavelength measurement of oxy- and deoxy-hemoglobin. Journal of Biomedical Optics, 10(l) 011015-l-011015-8, 2005. 

The performance of the temperature controller was measured in the tracking mode. Figure 6.18 shows a graph, where the temperature of one of the three microhotplates is kept at a constant temperature of 300 °C, the temperature of the second microhotplate is modulated using a sine wave of 10 mHz, while rectangular temperature steps of 150 °C, 200 °C, 250 °C, 300 °C, and 350 °C have been appHed to the third microhotplate. Temperature measurements on one of the hotplate that has been operated at constant temperature in the stabihzation mode showed a variation of less than 1 °C, even though the temperature of the neighboring hotplates was, at the same time, modulated dynamically (sine wave, ramp, steps). This is a consequence of the individual hotplate temperature control, without which thermal crosstalk between the hotplates would have been clearly detectable. The power dissipation of the chip is approximately 190 mW, when all three hotplates are simultaneously heated to 350 °C. In the power-down mode, the power consumption is reduced to 8.5 mW. 

Here E0 and vq are the ion beam energy and velocity, respectively and l is the flight length from the photodissociation region to the detector. An 8-mm-wide beam block is used for these measurements a narrower block results in crosstalk between the two halves of the anode. 

Thus, we have demonstrated, in the form of a diagram, the crosstalk between transverse velocity and a radial velocity measured by red shift. As we shall se in Section XII, the crosstalk between the radial velocity and the apparent transverse velocity is demonstrated by the use of another but similar diagram. By adding those two diagrams together we will finally find a method of evaluating the true velocity of the light source. 

Ruled Line Target. For the measurement of pincushion distortion, we decided to examine a ruled line target. It turned out that the intensity profiles obtained for these measurements were also useful for evaluation of the distortion caused by the pulsing of the SIT vidicon and also for measurement of channel-to-channel crosstalk. 

Channel-to-Channel Crosstalk. In one of the brochures supplied by the manufacturer of the OMA the channel-to-channel crosstalk for the SIT vidicon is stated in these terms with a 10 ym line centered on a channel, more than 60% of the signal amplitude is centered in that channel and more than 98% of the signal is in that channel and the two adjacent channels. Some of the patterns obtained from the ruled disk studies were examined to see if they were suitable for the measurement of crosstalk. 

Even before the introduction of miniaturized biosensor arrays, however, some systems able to simultaneously measure glucose and lactate had been reported in the literature. One example is provided by Osborne et al. [157], who described plastic film carbon electrodes fabricated in a split-disk configuration and then modified to obtain a dual biosensor. They achieved a continuous monitoring of these metabolites by placing the dual electrode in a thin-layer radial flow cell coupled to a microdialysis probe. The stability of the sensors was sufficient for short-term in vivo experiments in which the crosstalk, i.e., the percentage of current measured by one biosensor but due to product generated by the partner biosensor, was acceptable for an in vivo application. 

Measuring Crosstalk between Pathways - Biosynthesis of Isoprenoids in Plants 688... 

A comprehensive overview of frequency-domain DOT techniques is given in [88]. Particular instraments are described in [166, 347, 410]. It is commonly believed that modulation techniques are less expensive and achieve shorter acquisition times, whereas TCSPC delivers a better absolute accuracy of optical tissue properties. It must be doubted that this general statement is correct for any particular instrument. Certainly, relatively inexpensive frequency-domain instruments can be built by using sine-wave-modulated LEDs, standard avalanche photodiodes, and radio or cellphone receiver chips. Instruments of this type usually have a considerable amplitude-phase crosstalk". Amplitude-phase crosstalk is a dependence of the measured phase on the amplitude of the signal. It results from nonlinearity in the detectors, amplifiers, and mixers, and from synchronous signal pickup [6]. This makes it difficult to obtain absolute optical tissue properties. A carefully designed system [382] reached a systematic phase error of 0.5° at 100 MHz. A system that compensates the amplitude-phase crosstalk via a reference channel reached an RMS phase error of 0.2° at 100 MHz [370]. These phase errors correspond to a time shift of 14 ps and 5.5 ps RMS, respectively. 

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