These parameters assume that the record is printed on 8 1/2" by 11" paper. Series 1 is the amplitude response and Series 2 is the velocity response. The instrument is a Streckeisen STS-1.
This information is derived from the Excel spread sheet: cor_resp.xls.
The graph below shows how the STS-1 compares with other instruments.
The reference document is:
http://dmc.iris.washington.edu/stations/seisWorkshop04/iris_sensor_ws_9.19.05.pdf
