Boonton Electronic 9200A Multímetro digital
The instrument is microprocessor-based with unique features
that make it useful for systems requirements as well as for
manual operation. The basic instrument can measure RF
voltage levels from 200 microvolts to 3 volts over a
frequency range from 10 kHz to 1.2 GHz. An optional Model
952005 100:1 Voltage Divider extends the voltage range to
300 V up to 700 MHz. A 50-ohm terminated RF sensor, Model
952009, is also available to measure RF voltage levels from
200 microvolts to 3 volts over a frequency range from 100
kHz to 2.5 GHz. Option 9200A-03 adds a second complete input
section that allows the connection of an additional RF Probe
for simultaneous measurements of two voltage levels.
Measured RF levels can be displayed directly in mV, dBV,
dBmV, dB relative to an arbitrary reference, or dBm (dB
relative to 1 mW across any impedance between 50 ohms and
600 ohms). Typical uses of the instrument include:
a. Measurement of transistor parameters.
b. S WR and return loss measurements with directional
couplers, reflection coefficient bridges, and slotted lines.
c. Gain and loss measurements of wide-band amplifiers.
d. Adjustment of tuned circuits in narrow-band amplifiers.
e. Adjustment, performance measurements, and parameter
evaluation of RF filters.
f. Measurement of SWR, return loss, and attenuation of RF
g. Measurement of output levels of signal generators,
adjustment of baluns, harmonic distortion measurements of RF
signals, and adjustment of RF circuits for minimum voltage
(null) or maximum voltage (peak).
1-5. DESCRIPTION OF EQUIPMENT.
1-6. The instrument is packaged as a compact bench unit with
optional adjustable-angle bail. Hardware kits to accommodate
either one or two instruments for rack mounting are also
available as options. The basic characteristics of the
instrument include high reliability, fast warmup, long
intervals between calibration, good serviceability, and
light weight. Incorporation of a microprocessor, together
with a stored-program memory and a non-volatile memory,
result in performance features and operating convenience not
previously available in a general-purpose RF millivoltmeter.
Among the outstanding performance features are:
a. Wide Frequency Range. The calibrated frequency range of
the instrument is determined by the Probe
used with the
instrument. The Model 952001 RF Probe
supplied with the
instrument provides calibrated indications from 10 kHz to
1.2 GHz, with uncalibrated response to beyond 8 GHz. An
optional Model 952009 RF Sensor provides calibrated, 50-ohm
terminated indications from 100 kHz to 2.5 GHz.
Sensitivity and range linearization data for the Probe
supplied with the instrument is stored in non-volatile
memory. If another Probe
is used with the instrument, data
for this Probe
must be entered into non-volatile memory
before using the Probe
. Data entry is a simple procedure,
requiring only operation of an internal switch and entry of
data through the front-panel keys.
No further calibration is necessary.
b. Wide Measurement Range. The instrument has eight voltage
measurement ranges from 1 mV to 3 volts full scale, arranged
in a 1-3-10 sequence. In the dB measurement modes, it covers
a range of 80 dB in 8 ranges, with 0.01 dB resolution. The
measurement capability of the instrument can be extended to
300 volts at frequencies up to 700 MHz through use of the
optional Model 952005 100:1 Voltage Divider.
c. True RMS Response. Waveform response of the instrument
is true RMS for inputs below 30 mV, allowing accurate
voltage measurements with all types of waveforms. Probe
waveform response changes gradually as the input voltage is
raised above 30 mV approaching peak-to-peak at the higher
levels. The instrument shapes the response digitally to
indicate RMS voltage, provided that the input is reasonably
sinusoidal, as with CW or FM input signals.
d. Low Noise. The instrument has been designed and
constructed to minimize noise from all sources. The Probe
cable is of a special low-noise design; vigorous flexing
causes only momentary, minor deflections on the most
sensitive range of the instrument. The probes are
insensitive to shock and vibration; even Sharp
barrel causes no visible deflection on any range.
Internal signal amplification occurs at approximately 94Hz,
thereby reducing susceptibility to 50 or 60 Hz fields. A
low-noise solid-state chopper is used.
e. Key Selection of Measurement Modes. A choice of
measurement modes is available to the operator. Measurements
in terms of mV, dBV, dBmV, dB relative to an arbitrarily
chosen reference, or dBm (dB relative to 1 mW across any
impedance between 50 and 600 ohms) can be selected by merely
pressing the appropriate front-panel key. The keyboard also
allows entry of dB reference levels and impedance values for
these measurement modes.
f. Display. Measured values are displayed on a 4-digit, LED
type readout with decimal points and minus sign.
Annunciators associated with the display indicate the units
of measurement. The result is a clear, direct, unambiguous
readout that minimizes the possibility of misinterpretation.
The display is also used to show data being entered into
non-volatile memory and to display data recalled from
g. Analog Indications. A front-panel meter provides relative
RF level indications for peaking or nulling applications. A
rear-panel dc output supplies 10 volts full scale that is
linear with voltage in the mV mode, or linear in dB over the
entire 80 dB range in any of the dB modes.
h. Automatic Ranging. Autoranging under control of the
microprocessor eliminates the need for manual ranging by the
operator. Alternately, a measurement range can be retained
for measurements, if desired, by selecting a range hold
mode. Application of input levels beyond the measurement
capability of the instrument in the autorange mode or
outside the selected range in the range hold mode results in
an error indication on the display.
i. Automatic Zeroing. An automatic zeroing circuit
eliminates the need for tedious, often inaccurate manual
zeroing. With zero input to the Probe
, pressing the front-
panel ZERO key causes the microprocessor to compute and
store zero corrections for each range, which are applied to
subsequent readings. A logic transition is available at a
rear-panel connector for automatic turn-off of a source
during the automatic zeroing sequence.
j. Stored Probe
Data. Sensitivity and range linearization
data for two probes may be stored in the instrument
non-volatile memory. Probe
data is written into memory at
the factory for probes ordered with the instrument; Probe
data may also be written into memory quickly and easily in
the field. A hard copy of stored data is provided under the
right side cover of the instrument. The microprocessor
corrects measurements automatically in accordance with the
k. High/Low dB Limits. High and low dB limits can be entered
through the instrument keyboard. A panel annunciator
indicates when either limit has been exceeded, whether the
instrument is operating in the mV or any dB mode. Rear-panel
TTL outputs also provide remote indications of out-of-limit
1. Solid-state Chopper. Signal amplification in the
instrument occurs at approximately 94 Hz. Input signals from
are converted into 94 Hz signals by a solid-state,
low-level input modulator (chopper), which represents a
distinct improvement over electromechanical choppers.
Extended service life is assured through the elimination of
contact wear, contamination, and other problems associated
with electromechanical choppers.
m. Maintenance. The instrument is designed for easy
maintenance. Accessibility to all printed circuit boards is
excellent, all interconnecting cables are Plug-In
, and all
active devices are socket-mounted. Connection facilities for
signature analysis are incorporated, and special diagnostic
ROMs are available. Digital circuit troubles can be
localized rapidly and accurately using the signature-
analysis maintenance technique, thereby reducing instrument