hpmx-2003 ETC-unknow, hpmx-2003 Datasheet - Page 9

• Manufacturer Part Number: hpmx-2003
• Description: Silicon Bipolar Rfic Vector Modulator
• Manufacturer: ETC-unknow

HPMX-2003 Modulation
Spectrum Diagrams
Figure 20, below, shows the test
setup that was used to generate
the modulation spectrum dia-
grams that appear on the GSM,
JDC and NADC applications pages
of this data sheet. The major dif-
ferences between the tests are
summarized in the table below.
CLOCK
Figure 20. Test Equipment Setup for Modulation Spectrum Diagrams.
SPECTRUM ANALYZER
System
PRBS GENERATOR
NADC
GSM
JDC
GENERATOR
PROCESSOR
BASEBAND
HP-8563E
FUNCTION
HP-3314A
HP-3780A
HP-8657B
HP-8657D
OR
DATA
Bit Clock Frequency
Q
I
48.6 kHz
270 kHz
42 kHz
ALL R = 5 k
/4DQPSK Q INPUT
I ref
1
OP-AMP CIRCUIT
(SEE ABOVE)
+5 V
OP-AMP: TL-084
The modulation spectra are cre-
ated by setting the function gen-
erator to the appropriate bit-clock
frequency. The pattern generator
is set to produce a pseudorandom
serial bit stream (n = 20) that is
NRZ coded. The pseudorandom
bit stream which simulates the
serial data in a digital phone is fed
to the base-band processor that
splits it into a two bit parallel
HPMX-2003/5
0.3 GMSK (HP 8657B)
= 0.35 /4 DQPSK (HP 8657D)
= 0.5 /4 DQPSK (HP 8657D)
H
•
•
Baseband Filter
–
+
I + 2.5 V TO 1
2.5 V TO I ref
Q + 2.5 V TO 2
2.5 V TO Q ref
I CHANNEL IS IDENTICAL
7-46
Q ref
2
SIGNAL GENERATOR
Q + 2.5 V
Qref = 2.5 V
835-950 MHz
HP-8657B
stream (I and Q) and then filters
each according to the require-
ments of the digital telephone sys-
tem being simulated. The I and Q
signals from the baseband filter
are then DC offset by 2.5 V using
the op-amp circuit. The output of
the modulator is monitored using
a spectrum analyzer.
Channel (LO) Frequency
900 MHz
835 MHz
950 MHz