MMFM-QPM-4N-2.5G
QPSK MODULATOR
TECHNICAL DESCRIPTION / APPLICATION
The block diagram for the Merrimac MMFM-QPM-4N-2.5G, QPSK
Modulator is shown above. The modulator network is composed of a stripline
quadrature hybrid, two MMIC biphase modulators, and a stripline power
combiner. The multilayer package provides a surface-mount interface, and
is suitable for pick-and-place assembly.
The RF input signal is split into two quadrature components, each of which
is biphase modulated by independent, bipolar, digital bit streams. The two
biphase pairs of quadrature vectors are summed by the power combiner,
yielding a resultant vector with four possible states, spaced 90 degrees
apart.
The principal advantage of QPSK Modulation is high spectral efficiency
and low probability of bit error. A QPSK modulator combines two
independent, orthogonal, biphase modulated channels of information onto
one RF carrier, and therefore requires half the spectrum of BPSK to transmit
the same amount of information. Although the bit error rate is higher for
QPSK than BPSK, it is lower than all other M-ary PSK modulation schemes.
In addition, since QPSK modulation encodes data by phase only, linear
power amplification is not required. This type of modulator therefore has
many applications in modern digital satellite communications, and navigation
systems such as GPS. The ability to directly modulate the QPSK signal at
final operating frequency further reduces system complexity and improves
overall performance at a more affordable price.
Merrimac Industries, Inc. / 41 Fairfield Place, West Caldwell, NJ 07006
Tel: 1.888.434.MMFM / Fax: 973.882.5990 / Email: MMFM@merrimacind.com / www.Multi-Mix.com
MMFM-QPM-4N-2.5G
GENERAL SPECIFICATIONS
ELECTRICAL
FREQUENCY
INSERTION LOSS
AMPLITUDE BALANCE
PHASE BALANCE
RF INPUT DRIVE LEVEL
RF IMPEDANCE
RF INPUT RETURN LOSS
RF OUTPUT IMPEDANCE
RF OUTPUT RETURN LOSS
IQ INPUT DRIVE LEVEL
IQ DATA BANDWIDTH
ISOLATION, RFin TO RFout
2.4 to 2.6 GHz
9 dB
1 dB
+/- 5 Degrees
0 dBm
50 Ohms, nominal
17 dB
50 Ohms, nominal
15 dB
+/- 20 mA
DC To 500 MHz
35 dB
MECHANICAL
SIZE / OUTLINE
WEIGHT
RF INTERFACE
0.80 x 0.80 x 0.13 inches
0.127 oz., (3.62 grams)
Surface Mount
ENVIRONMENTAL
OPERATING TEMPERATURE RANGE
-55 To +85 Degrees, C
Merrimac Industries, Inc. / 41 Fairfield Place, West Caldwell, NJ 07006
Tel: 1.888.434.MMFM / Fax: 973.882.5990 / Email: MMFM@merrimacind.com / www.Multi-Mix.com
stm32/stm8
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