SR844 200 MHz RF Lock-In Amplifier0 pages

High Frequency Lock-In Amplifier
SR844 — 200 MHz dual phase lock-in amplifier

SR844 200 MHz Lock-In Amplifier
· 25 kHz to 200 MHz frequency range
· 80 dB dynamic reserve
· Time constants from 100 µs to 30 ks
(6, 12, 18 or 24 dB/oct rolloff)
· “No Time Constant” mode
(10 µs to 20 µs update rate)
· Auto-gain, -phase, -reserve and -offset
· Two 16-bit DACs and ADCs

The SR844 is the widest bandwidth lock-in amplifier
available. It provides uncompromised performance with a
frequency range of 25 kHz to 200 MHz and up to 80 dB of
drift-free dynamic reserve. It includes the many features, ease
of operation, and programmability that you’ve come to expect
from SRS DSP ­ock-in amplifiers.
l
Digital Technology
The SR844 uses the same advanced DSP technology found
in the SR850, SR830 and SR810 lock-in ­mplifiers. DSP
a
offers many advantages over analog instruments — high
dynamic reserve, low zero-drift, accurate RF phase shifts and
orthogonality, and digital output filtering.
Signal Input

· Internal or external reference

The SR844 has both 50 Ω and 1 MΩ inputs. The 1 MΩ input
is used with high source impedances at low ­requencies, or
f
with a standard 10× scope probe. The 50 Ω input ­ rovides the
p
best RF signal matching. Up to 60 dB of RF attenuation
­
or 20 dB of RF gain can be selected in 20 dB increments.
Full-scale sensitivities range from 1 Vrms (+13 dBm) to
100 nVrms (–127 dBm). Gain allocation can be optimized to
provide up to 80 dB of dynamic reserve.

· GPIB and RS-232 interfaces

Reference

· SR844 ... $8450 (U.S. list)

Stanford Research Systemst
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The SR844 offers both external and internal reference
operation. In both cases, the entire 25 kHz to 200 MHz

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phone: (408)744-9040
www.thinkSRS.com