6 GHz True RMS Power Meter
with Bus-Powered USB Connectivity
NI USB-5680
NEW!
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True RMS power measurements
Diode power meter
-40 to +23 dBm power range
50 MHz to 6 GHz frequency range
10 and 100 Hz typical
channel bandwidth
±0.13 dB accuracy at <+18 dBm
±0.18 dB accuracy at
≥+18
dBm
Internal zeroing capability
<3 percent sensor linearity
Standing wave ratio <1.2 to 6 GHz
100 mA typical power consumption
USB bus connectivity
N-type connector
Operating System
• Windows Vista/XP/2000
Recommended Software
• LabVIEW
• LabWindows
™
/CVI
Driver Software (included)
• NI-568x
Calibration
• Gain and offset self-calibration
• 1-year external calibration cycle
>>
For complete specifications, visit
ni.com/manuals
and search for
USB-5680 Specifications.
Overview
The National Instruments USB-5680 is a 6 GHz true RMS (root-mean-
square) power meter that features high measurement accuracy and wide
dynamic range. As a true RMS power meter, the NI USB-5680 is ideal
for measuring the power of continuous wave (CW) signals. In addition,
it offers better than ±0.18 dB of linearity across all frequency ranges and
all power levels. This functionality, combined with a flexible API, makes
it ideal for measuring path loss in automated test applications. In
addition, its small size (less than 9.6 cubic in.) frees up valuable rack
space without sacrificing performance. One of the biggest benefits of the
USB-5680 is its USB connectivity. Powered solely from the USB cable, it
consumes only 100 mA of current. Thus, you can use this power meter in
both production test and field applications with a laptop. Moreover, USB
connectivity helps you easily integrate the power meter with PC and PXI
systems in an automated test environment.
Architecture
The USB-5680 RF power meter features a dual-path architecture to
achieve 63 dB of dynamic range. This architecture improves power
measurement accuracy by ensuring that the diode sensors are used in
their most linear region. A block diagram of the USB-5680 architecture
is shown in Figure 1.
As Figure 1 shows, the first measurement range is from -5 to +23 dBm
and the second is from -40 to -5 dBm. This accounts for a combined
dynamic range of -40 to +23 dBm with a single power head.
27 dB
Attenuator
Detector A
Averaging
Pre-Amp
(-5 to +23 dBm)
Input
DC Block
10 dB
Attenuator
6 dB
Splitter
ADC
Microprocessor
USB
(-40 to -5 dBm)
6 dB
Attenuator
Averaging
Pre-Amp
Detector B
Figure 1. Block Diagram of the NI USB-5680
NI [ NATIONAL INSTRUMENTS CORPORATION ]
