Record menu.
Notice that the software is set so 1500 readings are made by the Apple IIe for each of the four seismometers from the A/D board, and these 1500 values are averaged to yield one value that is reported for each seismometer. I used this averaging technique to suppress the high frequency components of the signals, which was primarily background "noise" at our site. Notice also that every point on the displayed seismogram consists of four averaged values, representing 6000 individual determinations per seismometer per point. The Apple IIe was sufficiently "fast" to manage the system of four seismometers using Ron Jackson's excellent software, which was written in 6502 assembly language to achieve this level of speed and efficiency.