HP 85027A/B/C General Information
To keep this manual as current and accurate as possible, Hewlett-Packard recommends
that you periodically request the latest manual changes supplement as it may contain
error correction information as well as change information. The supplement for this
manual is keyed to the manual’s print date and part number (on the title page) and is
available free from Hewlett-Packard.
DESCRIPTION
The HP 85027 bridges are microwave directional bridges designed for making
modulated (AC) or unmodulated (DC) scalar reflection measurements with the HP
8757A scalar network analyzer and AC measurements with the HP 8765A and
HP 8755C. A single zero-biased Schottky diode detector in the bridge performs
reflection measurements by sampling the return loss of the device under test. A detector
can be added for simultaneous transmission measurements. A power splitter can be used
with the bridge or detector or both for ratio measurements. In all modes, typically the
RF input signal is supplied by a sweep oscillator or a synthesized sweeper.
The frequency range and connector type of each bridge appears below and in Table
1—1.
HP85027A
HP85027B
HP85027C
Frequency range (GHz)
0.01 to 18.0
0.01-26.5
0.01-18.0
Input Connector
Type N (f)
3.5mm (f)
Type N (f)
Test Port Connector
APC~7*
3.5mm (f)
Type N (f)
*APC.7 is a registered trademark of the Bunker-Ramo Corporation.
EQUIPMENT REQUIRED BUT NOT SUPPLIED
The following equipment is required for use with the HP 85027 in making reflection,
transmission and ratio measurements:
Scalar Network Analyzer
The frequency range of the three following analyzers is determined by the HP 85027
directional bridge in use.
HP 8757 A: this scalar network analyzer is a microprocessor based four-channel, three
input (four with Option 001) receiver with integral digital display. At RF and
microwave frequencies, it makes scalar transmission and reflection measurements over a
dynamic range of +16 dBm to -60 dBm and amplitude ratio measurements up to 152 dB.
The HP 8757A is completely programmable through HP-lB (Hewlett-Packard Interface
Bus, HP’s hardware, software, documentation and support for IEEE-488 and IEC 625).
Additionally the HP 8757A can control a plotter, a printer, such as the Thinkjet printer,
and a swept source through the 8757 System Interface.
The HP 8757A offers both AC and DC detection techniques. The AC technique
involves modulating the source signal at 27.8 kHz. Note that in this manual the
modulation frequency of 27.8 kHz is actually 27.778 kHz. The DC detection technique
modulates the input signal at 27.8 kHz within the bridge, after the DUT.
HP 8756A: this scalar network analyzer is also a microprocessor based receiver with
its own digital display. With its dual channels, it makes scalar transmission and
reflection measurements at RF and microwave frequencies over a dynamic range of -50
dBm to +10 dBm. It can nieasure amplitude ratios up to 60 dB. It is completely
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