Negative amplitude means the signal is attenuated relative to a reference point, so if you see e.g. -20dB, it means the signal is 1/10th of the reference value. dB on it's own is unitless, so you will see things like dBm (relative to 1mW â 0dB = 1mW), or dBV (relative to 1V â 0dB = 1V).
In Colorado, the offer is valid at the Denver Zoo and the Denver Art Museum. However, the Denver Art Museum is Sunday only, because they already offer free admission to everyone on the first Saturday of the month. This list does change, so check the Museums on Us website, before you go.
Fort Worth Zoo Hours: The zoo is open 365 days per year. From October 29, 2012 to February 15, 2013 the zooâs opening hours are from 10:00 a.m. to 4:00 p.m. From February 16, 2013 to March 22, 2013 the zooâs opening hours are from 10:00 a.m. to 5:00 p.m.