PSN-L Email List Message

Subject: Broadband station response
From: S-T Morrissey sean@...........
Date: Fri, 19 May 2000 12:34:39 -0500 (CDT)

Here is some additional information on the channel designations at
a broadgand station using SEED name conventions:
(SEED = Standard for the Exchange of Earthquake Data ).

Note that the SEED names are different from the former channel
streem descriptor names: ie VBB-Z is BHZ, LP-Z is LHZ, VLP-? is VH?,
VSP-? is SH?, etc. The names do not exactly specify the sample rate,
but the conventions of the IRIS stations are preferred.

here is the file vbb_system_description from CCM:

	(This is the response to the "r" command in any data retrieval mode.)

	Station :   CCM   Cathedral Cave, Missouri
            	Lat: 38.0557 N  Lon:-91.2446 W  Elev:222.5m  
            	(51 meters below the local surface)
	Components: Z  : + = ground motion up                  
                N  : + = ground motion north
                E  : + = ground motion east
	Digitizer: Quanterra Q980 split system (9 24-bit channels).

	Streams:    VBB : 20 SPS: on 24-bit channels, from Streckeisen STS-1
 	           seismometers.  Instrument response is flat
 	           to velocity from 10 Hz to 360 sec;  Sensitivities are
  	           Z = 2278 Vsec/m;    N = 2142 Vsec/m;    E = 2058 Vsec/m. 
  	           Recorded continuously on line and on tape.
 	     LP :  1 SPS: derived by constant-time-delay Finite Impulse
 	         Response (FIR) digital filter from VBB stream in real
   	         time, cutoff at 2.7 S period. 4x Gain. Recorded continuously.
	      VLP : 0.1 SPS: derived by FIR filter from LP stream in real
  	          time, cutoff at 27 S period. 4x Gain. Recorded continuously.
  	    ULP : 0.01 SPS: derived by FIR filter from VLP stream in real
   	         time, cutoff at 270 S period. Recorded continuously.
  	    Micro-Barometer Data, as of 24 Feb. 1995:
  	        U data is direct barometer at 419.43 counts/Pascal;
  	        V data is 3600 sec high pass of U;
 	        W data is 100 sec high pass of U.
     	    U,V,W VBB: 20 SPS: on 24-bit channels, same response as STS-1s
 	     LP, VLP, and ULP barometric data also recorded continuously.
     Very high gain, short period channels for the CTBT (Comprehensive Test
	 Ban Treaty) from a separate set of 1 hz seismometers:
 	     VSP : 40 SPS: on 24-bit channels, from GS-13 seismometers.
  	          Recording continuously but NOT event detected.
   	         (The amplifiers for the GS-13's are flat to 25 hz.)
   	    ESP : 80 SPS: on 24-bit channels, from GS-13 seismometers.
 	           Event recorded only. (online buffers; not on tape)
   	   Various SOH channels are also recorded, including STS-1 mass position
   	   (VMZ,VMN,VME),  DA supply voltage (VE1,UE1),  average free packets
   	   (AFP),  clock drift and corrections (ACD, AFC),  and DA instrument 
	    temperature (VKI).
		Note: FIR filter delays are accounted for in the header reported
		          with the data.
Response:   Basic response for the LP,  VLP,  and ULP channels is flat to
	    ground velocity from the FIR filter upper cutoff to the
            second-order lower corner at 360 S period. 


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Larry Cochrane <cochrane@..............>