Heating of the card may slightly affects the absolute level calibration

The VXpocket (and possibly the PCXpocket) card can get quite hot (45degC) when positioned in the PC Card slot with anther PC card. This affects the input sensitivity slightly. Tests have shown that the input sensitivity is directly related to the card's temperature and stabilizes after about one hour. The change in the input sensitivity is approximately 0.001dB/degC. The maximum difference seems to be ~0.015 dB. This is not significant for acoustic measurements but electrical measurements may demand better accuracy. In this case it is recommended to leave the computer on for about 1 hour before performing critical measurements. The output sensitivity is unaffected by operating temperature of the sound card.