BNC 630 - Manual (Page 7)

2
1.1 Description
Position
Value
*
FSK
∅ M
SSB
Burst
AM
DTMF Gen
Power
Measure
Sweep
FM
DTMF Det
#
MHz
dBm
KHz
Vp-p
Sec
Hz
MV p-p
mS
Other
Clear
One Touch
Mode Selection
Field
Digit Field
Remote
SYNC
Out
SIG
Out
. з з
1
Trigger
9 8 7
6
0
5
2 3
-
Offset
Recall
Store
и и
к к
й й
Sinewave
Function
Arbitrary
Pulse
Ш Ш Ч Ч
Mode
4
Figure 1.1-1: 630 front panel
The Model 630 is a versatile signal source capable of generating a variety of waveforms, including CW and wideband sweeps
from D.C. to 21.5 MHz in steps of .01 Hz. The signals are generated using direct digital waveform synthesis (DDS) techniques for
high accuracy and precision. A wide variety of modulation types are available, including AM, FM, PM, and FSK. A high speed
Digital Signal Processor (DSP) controls every aspect of the DDS system and is used internally for the precise generation and
processing of all modulating waveforms. The use of DSP technology makes possible additional modes which process or analyze an
externally applied signal such as DTMF detection and power level measurement.
The 630 is capable of supplying an output level of 20.0 Vp-p with an offset voltage of +/- 12.0V (unloaded). The output
impedance is 50 ohms, therefore the 50 ohm loaded output level is 10.0 Vp-p, with an offset voltage capability of +/- 6.0V. The
output level and offset voltages can be adjusted with a resolution of 1 mV. Output levels can also be specified in dBm with
.1 dBm resolution. The unit is factory calibrated to produce accurate output levels and DC offset voltages.
The front panel, shown in figure 1.1-1, has two output connectors. The SIG Out connector is the main signal output. The SYNC
Out connector is a TTL/CMOS compatible squarewave output. It is a "hardlimited" version of the main output and is available in all
modes. The SYNC Out swings 0V to +5V and is useful for driving digital circuitry.
The front panel of the Model 630 includes a full numeric keypad which makes it quick and easy to select a mode and enter or edit
all parameters pertinent to that mode. In addition, a rotary knob allows quick adjustment of any numeric value and gives the user the
ability to manually adjust a value across a wide range without having to retype.
The LCD display is a large 2 line by 40 column illuminated display. It is large enough to display all operating parameters
simultaneously and thus eliminate tedious submenus.
The user can select a modulating waveform that is either internally generated or externally supplied. External signals in the DC to
35 KHz range are input to the 630 through the External Modulation In connector on the rear of the unit. This input is high
impedance (about 30K ohms) to avoid loading the source of the signal.
The unit also features an external digital input on the rear of the unit which serves several purposes depending on the mode. For
most modes, it serves as a gate to switch the RF output signal on and off. In external FSK or BPSK mode, it is a high speed data
input for FSK or BPSK digital modulation of the output waveform at rates up to 3 MHz. In modes that have a trigger function
(Burst, Triggered Sweep, etc.) this input serves as an external trigger which triggers a sweep or burst on the rising edge of the input.
The unit also features an EIA-RS232 connector on the rear of the unit. This permits the user to remotely control the 630 using
ASCII characters. No special hardware or protocols are needed; any dumb terminal or computer serial port can be used. An on-line
help menu which lists all remote control commands to the terminal is available. The baud rate is adjustable up to 115.2 KBaud.
Software upgrades are also downloaded to internal Flash memory using this port.
An Arbitrary Waveform Generator lets the user design custom waveforms on a PC and download them to the 630 for generation.
Up to 32,768 unique points may be specified and generated by a 12 bit DAC with a sampling adjustable from 0 Hz to 40 MHz in .01
Hz steps. A logic waveform may also be generated simultaneously with the analog waveform. The unit will accept many popular data
formats for maximum flexibility. Arbitrary Waveforms may be conveniently saved to nonvolatile memory.
Included with the Arbitrary Waveform Generator is a full featured Function Generator and Pulse Generator. The function
generator offers a set of pre-stored waveforms which are generated using the Arbitrary Waveform system. The Pulse Generator
allows the user to generate pulse waveforms with varying amplitude, offset, frequency and duty cycle.