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High
Performance Central Site Telemetry Discriminator
Model
TC-20DS
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The VLF series of analog field telemetry system represents a flexible
means for transmitting seismic signals through analog transmission
(telephone or radio). The TC-20DS is a low power, multi channel central
site discriminator. It is a field proven system, with many worldwide
installations. Compared to other systems, it offers additional features,
lower cost, and improved performance
The discriminator features low noise and drift, complementary filters
to those found in the field telemetry system to assure a high degree
of anti alias protection for digitally recorded data, a highly selective
three pole input bandpass filter, fast acting squelch circuit, highly
linear frequency to voltage converter, low pass and high pass data
filters, and an output LED display circuit. A single PC card can be
ordered in 1, 2, or 3-channel configurations thus conserving valuable
rack space. The TC-20DS is low power and features a minimum of adjustments
to attain maximum performance from the telemetry system. The convenient
output display indicates the positive and negative offsets, permitting
the user an easy visual method of verifying that each channel's offset
is properly nulled. The unit is designed for the CG-x series central
site racks, housing up to 26 discriminator cards or 78 individual
data discriminators. For portable and rapid deployment applications
an optional field case is available.
Coupled with the high performance field telemetry system (model PTS-3bgx)
at the field site, this system offers the user a simple, easy to maintain,
cost effective transmission system. Other system components include
external multi channel multiplexer (Model PTS-9MX), lightning suppression
systems (Model LPS-x), external signal band pass, high pass, or low
pass filters (Model TC-70X), line amplifier (Model TC-80X), central
site digitizing and recording systems (Model DAS-6102PC), and analysis
software.
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FEATURES
- Demodulates up to 3 channels from a single data
stream
- Anti alias filtering
- Fast acting squelch
- Output LED display
- Minimal drift
- Low Noise
- Minimum adjustment required
- Easy to install and use
- Central site or portable rack systems available
- Expandable
- High reliability, field proven
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SPECIFICATIONS |
INPUT CHANNELS |
Number of Input Channels: |
1 through 3("x" indicates number
of channels) |
Audio Input Level: |
15Vp-p max |
Normal Input Amplitude: |
500 mVp-p per carrier |
Input Impedance: |
100 K Ohms |
Input Coupling: |
A/C coupled, single
ended |
Input Filter Type: |
3 pole bandpass |
Squelch Level: |
125 mVp-p |
Unsquelch Level: |
250 mVp-p |
Squelch Attack Time: |
1 cycle of input signal |
Squelch Release Time
Delay: |
2 seconds |
OUTPUT |
Output Level: |
±5V DC for ±125 Hz
deviation (nominal) |
Output Level Maximum: |
±5.75 VDC |
Output Impedance: |
Less than 10 ohm |
Output Noise: |
5 mVp-p or less |
Output Offset: |
5 mVDC max |
FILTERS |
High Pass Filter: |
0.1 Hz (others available) |
Low Pass Filter: |
5 pole 25 Hz Butterworth
(others available) |
HOW
TO ORDER |
POWER |
Basic TC-20DS Configuration |
The standard configuration
includes 1channel and manual. |
Channel Configuration |
option -2 (2 channels) or -3 (3 channels)
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Optional Low Pass Filters |
-xxLP (where xx indicates frequency) |
Optional High Pass Filters |
option -xxHP (where xx indicates frequency) |
Sensor Options |
EP-105 Broadband,
SP-400 Medium Period Seismometer,
R-1 Rotational Seismometer
EV-12 Force Balanced Velocity/Accelerometer
EA-120 Force Balanced Accelerometer
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Recorder Options |
DAS-6102
Field Recorder
DAS-6102-PC Desktop Recorder |
Lightning Protection |
LPS-xx (depends on what
is being protected, consult factory) |
Other |
Card Cage
Radios
Anntenas
Solar Systems
(Consult factory for correct configuration)
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General Spares |
None |
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S Printer
Friendly Format For Specifications
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Operating Voltage: |
±11 - 15 VDC (nominal) |
Operating Current: |
10mA per channel |
USER INTERFACE |
Adjustments: |
Bandpass filter frequency
adjustment, 3 positions
A/C balance
Span |
Indicators: |
DC positive offset
(green LED)
DC negative offset (green LED)
Squelch |
Front Panel Test Points: |
Filter out
Ground
Signal out |
SYSTEM SPECIFICATIONS |
Dimensions: |
W 4" x L 9" x D 0.6"
Card |
Optional Field Box style: |
NEMA 4X die cast painted aluminum |
Operating Temperature: |
-30°C to +65°C |
Humidity: |
0-100% RH, non condensing (in field
case) |
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Specifications Subject
to Change Without Notice |
©eentec 2000, 2003,2007 |
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