HP 3335A - Connector and Interface Descriptions; Front and Rear Panel Connectors; External Level Input; HP-IB System Operations

Model 3335A
If the 3335A is under remote control, it can be returned to
local control (control by keyboard inputs) by activating the
LOCAL key providing a local lockout command has not
been sent by the HP-IB system controller.
3-56. Front Panel Output Connectors.
A (RGSS
The output of the -hp- 3335A is directly
coupled. Do not allow external dc currents to
develop more than S volts across the output
terminals. For Option 002/004 and Option 003
the de voltage across the output should not be
greater than 10 volts.
3-57. The front panel. contains the instrument output con-
nectors located in the right-most group labeled OUTPUT
and the SWEEP OUTPUT located in the FREQUENCY
group. The output connectors provide the programmed
output. The SWEEP OUTPUT provides a de voltage
between O and + 2 V proportional to the sweep when the
Synthesizer is in the sweep mode. When not in the sweep
mode the SWEEP OUTPUT is + 1 V. During the sweep, the
SWEEP OUTPUT is proportional to the frequency and can
be used to drive the horizontal sweep of a plotter or an
oscilloscope.
3-58. Rear Panel BNC Connectors.
3-59. 40/N Input. This is the input for the reference fre-
quency that essentially determines the frequency accuracy
and stability of the -hp- 3335A. As the name of the input
suggests, the reference frequency must be an integral sub
multiple of 40 MHz (ie., 40, 20, 13.333, 10, etc.). The
40 MHz master oscillator in the -hp- 3335A is phase locked
to this signal. Lock will occur with 40/N INPUT levels as
low as -7 dBm. When an external frequency reference is not
used, the 10 MHz REFerence OVEN OUTPUT is coupled
to this input with the BNC-to-BNC adapter.
3-60. 10 MHz REFerence OVEN OUTPUT. This is a refer-
ence frequency that is coupled to the 40/N INPUT when-
ever. an externa] frequency reference is not used. When it is
used, its accuracy and stability determine the accuracy and
stability of the -hp- 3335A output frequency. The para-
meters of this output are described in Table 1-1. They
depend on the Option selected.
3-61. 10 MHz OUTPUT. This output is used to lock the
phase of other synthesizers to the phase of the -hp- 3335A.
Its output level and output impedance are typically around
0 dBm and 50 ohms.
3-62. EXTernal LEVEL INPUT. This input is selected
using the INTERNAL LEVEL/EXT LEVEL INPUT switch
located on the rear panel. When it is selected, the dc level
on this input determines the output amplitude. The sensi-
tivity is non-linear, however, it is typically about .5 V rms
output per de volt input. With O volts dc on this input, the
maximum output amplitude of the -hp- 3335A is nominally
.5 volts rms into 50 ohms (or 75 ohms). An “UN—
Section HI
LEVELED” annunciator on the front panel will light
whenever this input is selected.
3-63. Remote Programming.
3-64. This part of Section HI contains a brief description
of the HP—IB operation and includes programming infor-
mation for operating the Model 3335A on the HP—IB. H
also includes information on the HP~IB connector, HP~IB
logic levels and programming codes.
3-65. The HP—iB. The HP--IB is a carefully defined instru-
mentation interface which simplifies the integration of
instruments, calculators and computers into systems. The
3335A is a fully programmable instrument interfacing with
the HP—IB by means of a rear panel HP—IB connector (see
Figure 3-1). The HP—IB connector is directly compatible
with the mating connectors on the -hp- 10631 (A, B or ©)
HP—IB Cable Assemblies.
3-66. HP—IB Logic Levels. The 3335A HP~—IB lines use
standard TTL levels and are low-true. The logic levels are:
Low = digital ground or 0 V to +0.4 V de
High = open or +2.5 V de to +5 V de
3-67. isolation. The 3335A is located from the HP--IB by
optical couplers. The components located on the HP—IB
side of the optical couplers are powered by a separate
+5 V power supply deriving power from an ungrounded
secondary transformer winding. This provides isolation of
the instrument from the bus.
3-68. Capability. The capability of a device connected to
the HP—IB is specified by its interface functions. The inter-
face functions of the 3335A are listed in Table 3-2 and indi-
cate the particular capability of that function as defined
in Appendix C of IEEE Std 488-1975. The interface func-
tions indicate what activity a device will respond to or that
which it is capable of initiating. Each item indicating a
device capability appears on the rear panel next to the
HP—IB connector.
3-69. The instrument will recognize a preset “listen”
address and accept bit-parallel, word (byte)-serial ASCH-
coded data. All data is received through the Data Input/
Output (DIO) lines of the HP—IB. The data transfer is con-
trolled by “handshake” lines DAV, NRFD and NDAC.
Figure 3-2 illustrates the “handshake” sequence of events
and describes each event during the transfer of data. More
detailed information is obtainable by ordering a copy of
“Condensed Description of the Hewlett-Packard Interface
Bus”, -hp- Part No. 59401-90030, Microfiche Part No.
59401-90090.
Table 3-2. Interface Functions.
Identification Description
SHG No source handshake capability
AH] Acceptor handshake capability
TË No talker capability i
L2 Basic listener
SRE No service request capability
Remote/Local capability
No paralle! poll capability
Device clear capability
No device trigger capability
No controler capability ovo zs
aug
a
EE A