MPT
1820VA is a vector attenuator in a 18-pin surface mount package of 1.0” X 0.9.” It is functionally equivalent to the combination
of an endless phase shifter and attenuator, for use at 1800 MHz to 2000MHz. MPT 1820VA may be used anywhere it is necessary to
control the amplitude and phase of a signal without introducing intermodulation
distortion, dispersion, or variation in group delay.
While MPT 1820VA is not architecturally similar to the combination of a phase shifter and
attenuator, it serves the same purpose and has several other advantages. For example,
there is no limitation on phase change. With negligible delay variation, phase can
increase or decrease continuously without reaching an end point. |
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The 1820VA can also transition directly from any attenuation and phase to any other
attenuation and phase. For example, minimum
attenuation at 0°
to minimum attenuation at 180°,
without a continuous phase transition from 0°
to 90°
to 180°.
These qualities make the 1820VA particularly useful in signal
cancellation systems where the phase and amplitude of one signal must be adjusted so that
it can be completely cancel another signal of arbitrary amplitude and phase.
Typical applications include gain and phase adjustment in the
cancellation loops of feed - forward amplifiers and in RF predistorters. Application notes
are available describing their use in these types of systems. |
