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1.0
DESCRIPTION
1.1 The Model 409B is a four-channel Direct Digi-
tal Synthesizer (DDS) in a small table top case with
RS232 serial control. The 409B provides four inde-
pendent, phase-synchronous sine wave (consult fac-
tory for LVCMOS) output signals, which can be set
from 0.0 Hz (DC) to 171 MHz in 0.1 Hz steps when
using the internal VCTCXO clock.
1.2 The 409B can also be used with an External
Clock input. An on-board programmable frequency
multiplier generates the master clock allowing user
configured frequency ranges. The multiplier can be
disabled for direct inputs up to 500 MHz for opti-
mum phase noise performance. When used with the
same external clock source, multiple 409B are phase
synchronous.
1.3 The /R option converts the External Clock input
to a 10.00 MHz reference input. Using the same
topology as our locking programmable oscillator
modules, this options allows locking to and tracking
of an external 10.00 MHz, with no binary round-off
errors. When this option is installed the accuracy
and stability of the output are equal to those of the
reference.
2.0
SPECIFICATIONS
2.1 OUTPUTS
TYPES: Four Sine simultaneously (four independent,
phase-synchronous outputs.)
IMPEDANCE: Sine: 50 Ω; LVCMOS: 50 Ω.
RANGE: 0.0 Hz to 171 MHz in 0.1 Hz steps (Sine out, int.
clock).
SINE AMPLITUDE: approximately 1 V
50Ω. Programmable from 0/1024 to 1023/1024 of Full
Scale (10-bits), or by scale factors of 1/2, 1/4, or 1/8.
PHASE: Each channel 14-bits programmable (0.022
FLATNESS: ±3dB from 1 kHz to 150 MHz referenced to
amplitude at 35 MHz, full scale.
2.2 LVCMOS AMPLITUDE
V
>=2.4V and V
<=0.4V when series terminated. Rise
oh
ol
and fall times <1.5ns. (>1 MHz, <125 MHz) (consult fac-
tory for LVCMOS)
2.3 CONTROL
Output frequencies, amplitudes (10-bits) and phases (14-
bits) are controlled by an RS232 serial port at 19.2kbaud,
NOVATECH INSTRUMENTS
or direct connection to the DDS generator. All settings
(except table mode data) can be saved in non-volatile
(EEPROM) memory via the RS232 port.
2.4 ACCURACY AND STABILITY
Accuracy: <±1.5ppm at 10 to 40
tional ±1ppm per year, 18 to 28
2.5 EXTERNAL CLOCK IN
LEVEL: 0.2 to 0.5 Vrms Sine or Square Wave. 50 Ω.
FREQUENCY: 10 MHz to 125 MHz with multiplier of 4 to
20 enabled. Direct input of 1 MHz to 500 MHz.
/R Option: 10.00 MHz, ±5ppm. Automatically detected.
Internal clock is locked to and tracks this value.
2.6 SPECTRAL PURITY
clock, full-scale output)
Phase Noise: <-120dBc, 10kHz offset, 10 MHz out.
Spurious:
Harmonic: <-65dBc below 1 MHz
(channel-channel isolation: <-60dBc)
2.7 TABLE MODE
On-board 4Mb static ram holds up to 32,768 profile
points in table mode allowing a different output in 100 µS
increments.
2.8 POWER REQUIREMENTS
+4.5 to +5.5 VDC <1Amp. AC adapter provided.
2.9 SIZE
39mm H, 107mm W, 172mm L, not including connectors.
2.10 CONNECTORS
(+4dBm) into
BNC for Sine Outputs and EXT CLK IN. DE9 for Serial
pp
Control. 2.5mm center positive power receptacle for +5
volts input. AC-adapter provided.
o
).
2.11 OPTIONS
Model 409B-AC adds two rear-panel SMA connectors for
external control of output update and table timing (see
AN002). /R Option converts the External Clock In to a
10.00 MHz external reference input (see Appendix B).
2
o
C. Stable to an addi-
o
C. (Internal Clock)
(Typ. 50Ω load, internal
<-60dBc below 10 MHz (typ. 300MHz span)
<-60dBc below 40 MHz
<-55dBc below 80 MHz
<-50dBc below 160 MHz
<-55dBc below 20 MHz
<-45dBc below 80 MHz
<-35dBc below 160 MHz
409B Manual, 17-Apr-2015
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