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Technical
Glossary - P
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| W,X,Y,Z | Spec.
Char., Number |
p
(See "pico")
P1dB
(See "1 dB Compression Point")
PA
(See "power amplifier")
Package
Container for a semiconductor die that protects
it and has electrodes that facilitate electrical
connection of the die to the external circuit.
Pad
Attenuator, or to attenuate.
Parameter
A measurable electrical characteristic.
Passband
The frequency interval that is propagated through
a filter with minimum insertion loss.
Passband
Ripple
The amplitude variation within the passband of
filter.
Passivation
A layer of material on a semiconductor die that
protects it from external contamination and chemically
ties up any unbound charges that may exist on
the surface as a result of the discontinuation
of the semiconductor crystal at the surface. For
silicon devices, the passivation is often a layer
of silicon dioxide (Si02) that is formed by oxidizing
the surface of the silicon at temperatures around
1000 °C. For gallium arsenide devices, a layer
of silicon nitride (Si3N4) is often deposited
on the surface of the GaAs for passivation.
Passive
Unable to amplify or produce energy.
Passive
Components
Devices that do not amplify or produce a signal.
Passive
Device
(See "passive components")
Passive
Network
(See "passive components")
Path
Loss
The reduction in transmitted power as measured
at a receiver due the distance the signal traveled
from the transmitter, atmospheric absorption and
other factors.
PCN
Personal Communications Network.
PCS
Personal Communications Services. A term used
in the United State for any mobile telephone services
in the 1900 MHz frequency band.
Peak
Power
The maximum instantaneous power of a signal.
Peak-to-Peak
Amplitude
(See "Peak-to-Peak")
Peak-to-Peak
The magnitude of the arithmetic difference between
the maximum and minimum values for a varying quantity.
Percent
Bandwidth
The bandwidth divided by the center frequency
of the band, expressed as a percentage.
Period
Duration.
Permeability
A measure of how much better a material is as
a path for magnetic flux as compared to free space.
The symbol for permeability is "µ".
For free space, µ = 1.
peta
A prefix that indicates a factor 1015, abbreviated
as "P."
Phase
In a periodic function, the fraction of a period
that has elapsed since some arbitrary reference
point.
Phase
Angle
The angle obtained by multiplying the phase of
a periodic function by 360 if the angle is to
be expressed in degrees, by 2p if the angle is
expressed in radians, or by 400 if the angle is
expressed in grads.
Phase
Lock
The technique of forcing the phase of an oscillator
to follow the phase of a second, highly stable
reference oscillator by comparing the phase angle
between the two signals and applying an appropriate
correction signal to the oscillator that is to
be controlled.
Phase
Modulation
The modification of the phase of a higher frequency,
constant magnitude carrier signal controlled by
the amplitude and phase of a lower frequency baseband
or audio signal.
Phase
Modulator
A circuit that produces phase modulation of a
carrier signal.
Phase
Noise
A measure of the random phase instability of a
signal.
Phase
Shift
The change in phase of a periodic quantity.
Phase
Shifter
A circuit or system that is designed to produce
phase shift.
PHS
Personal Handy Phone System
pico
A prefix that indicates a factor 10-12, abbreviated
as "p."
p-i-n
Diode
A three-layer semiconductor diode consisting of
an intrinsic layer separating heavily doped P
and N layers. The charge stored in the intrinsic
layer in conjunction with other diode parameters
determines the resistance of the diode at RF and
microwave frequencies. This resistance typically
ranges from kilohms to less than 1 ohm for a given
diode. A PIN diode is typically used as a switch
or attenuator element.
Pinch-Off
The cessation of drain-source current flow in
a field effect transistor.
Pinch-Off
Voltage
The gate-source voltage required to stop drain-source
current flow in a field effect transistor.
Planar
Of, pertaining to or contained in a single geometric
plane.
PM
(See "Phase Modulation")
PNP
(p-n-p) Transistor
A bipolar transistor with a p-type emitter, n-type
base and p-type collector.
Point
Contact
The original "microwave diode" made
in the 1950's by Microwave Associates. Microwave
Associates started a major new product program
in August 1952 to manufacture microwave diodes.
These diodes, now universally known as point contact
diodes, were the first widely used high frequency
semiconductors, and were used as mixer or detector
diodes in all high frequency receivers (radars
and radio links). Microwave Associates manufactured
these by pressing a pointed tungsten wire whisker
against a small silicon chip.
Post
Tuning Drift
For a voltage controlled oscillator, it is the
change in frequency of the oscillator after it
has been driven to and attained a new frequency
and after the tuning voltage has reached a stable
state.
Power
The rate of doing work. The unit of power is the
watt, abbreviated as "W" and equal to
1 joule per second (see "joule").
Power
Amplifier
An amplifier intended to increase the power of
a signal enough to drive a load such as an antenna.
Typically, power amplifiers also have large values
for P1dB, indicating low distortion at high output
power.
Power
Dissipation
The amount of electrical power converted to heat
by a device.
Power
Divider
A circuit that splits the power of an input signal
into two or more locations without producing impedance
mismatch.
PTD
(See "Post Tuning Drift")
P-type
(See "p-type material")
P-type
Material
A semiconductor material that has had acceptor
atoms added, thereby imparting a net positive
charge.
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