PSN-L Email List Message

Subject: low power VCO
From: sean@...........
Date: Thu, 3 May 2001 14:56:42 -0500 (CDT)


I can send you the schematic and artwork for the VCO that I designed
that was used in the 55 USGS telemetry stations in New Madrid, the
Aleutian network, as well as in Greece and Soviet Asia. At one time
Sprengnether was producing it for us as part of the micropower Amp/VCO
telemetry cannister.

It is a micropower system (power about 0.5ma at +.- 4.05 volts) with
active temperature compensation with the standard IRIG frequencies of
420, 680, 1020, 1360, 1700, 2040, 2720, 3060, and 3400 hz. It uses the
VCO section of the micropower CD4046, and LM4250 op-amps. The output 
is a sine derived by an 8-step summation. 

Unfortunately the design is pre-web, and nothing has been scanned. The
DC-DC converter design was published in BSSA long ago. 

"A 50-Milliwatt Power Converter to Replace Mercury Batteries in 
Seismic Amplifier/VCO Systems", Bull. Seism. Soc. Am., 72, .......

The whole telemetry cannister (same dia. but 3x as long as an L4-C seis)
operates on 4 ma at 13 volts from the VHF transmitter battery. Some are 
still in use.

If you send me an address, I can mail the info. If you only want one
board, I can probably send you a blank ready to load.


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