Table of Contents
Advertisement
Model 654A
Section I
SECTION
I
GENERAL INFORMATION
1-1. DESCRIPTION.
1-2. The Hewlett-Packard Model 654A Test Oscillator is an
ideal general purpose signal source whenever a flat balanced
or unbalanced test signal is required. Balanced outputs of
135 ohms, 150 ohms and 600 ohms have many uses in the
communications industry. Automatic leveling, together
with the expanded meter, make the 654A ideally suited to
voltmeter calibration or to test frequency response of
components during manufacture. The instrument is shown
in Figure 1-1 and the specifications are listed in Table 1-1.
General information relating to the instrument is listed in
Table 1-2. The information in Table 1-2 should not be
considered specifications.
1-3. The Model 654A is a stable, low distortion sine-wave
signal source with a flat frequency response of +/-0.5% over
the frequency range of 10 Hz to 10 MHz. The attenuators
allow the signal to be adjusted in 1 dB and 10 dB steps
from + 10
dBm
to -89
dBm, and the front
panel
AMPLITUDE control allows a continuous adjustment in
level of +1-1 dB from the settings shown on the OUTPUT
LEVEL
attenuators.
The
flat
frequency
response
is
achieved by automatic leveling circuits within the 654A.
1-4. Five output impedances are available, selected by a
front panel push-button control: these are 50 and 75 ohms
unbalanced and 135, 150 and 600 ohms balanced. Balance
is greater than 50 dB up to 1 MHz and greater than 40 dB
up to 5 MHz.
1-5. The meter scale is expanded to indicate 0 dBm at
center scale, with a total range of +/- 1 dBm. The metering
circuit monitors the signal level before the attenuators so
that the meter indication is independent of the attenuator
settings; the meter indicates the signal level set by the front
panel AMPLITUDE control. The output signal level into
the load is the algebraic sum of the meter indication and
the OUTPUT LEVEL attenuator settings.
1-6. An additional feature is the COUNTER OUTPUT rear
panel
BNC connector. This allows the Model 654A
frequency to be continuously monitored by an electronic
counter without interrupting measurements or affecting
terminal balance.
1-7. SUPPLIED ACCESSORIES.
Rack mount kit: -hp- Part No. 5060-0775.
1-8. RECOMMENDED ACCESSORIES.
-hp- 11048C
-hp- 11094A
-hp- 11095A
-hp- 11143A
50 ohm Feedthrough Termination
75 ohm Feedthrough Termination
600 ohm Feedthrough Termination
Balanced BNC to Alligator clip cable
1-9. INSTRUMENT AND MANUAL IDENTIFICATION.
1-10. Hewlett-Packard uses a two-section serial number.
The first section (prefix) identifies a series of instruments.
The last section (suffix) identifies a particular instrument
within the series. If a letter is included with the serial
number, it identifies the country in which the instrument
was manufactured. If the serial prefix of your instrument
differs from the one on the title page of this manual, a
change sheet will be supplied
to make
this manual
compatible with newer instruments or the backdating
information in Appendix C will adapt this manual to earlier
instruments.
All correspondence with Hewlett-Packard
should include the complete serial number.
1-1
Advertisement
Table of Contents
