Ramsey Electronics FZ-146 Specifications download pdf (Page 44)

FX 146 • 44

controlled, compared with another frequency, as is done in a PLL circuit.

See PHASE DETECTOR, PLL.

RSSI = "Received Signal Strength Indicator," a function of the MC13135 IC

and comparable circuits which permits MEASURING of the relative strength

of a received signal. A few microamps of variation can be interpreted as DB

(decibels) of signal strength.

RX = Abbreviation for receive, receiver, receiving. [See: TX]

SPEAKER-MIKE = speaker and microphone functions contained in the

same physical housing, as in the design of simple home intercoms. For ham

operators, this means that both speaker and microphone are in a

microphone casing with separate plugs from a common cord. Since such

accessories can use ANY style of plug for either mic or speaker function,

Ramsey Electronics has adopted the popular ICOM-compatible standard for

the FX transceivers.

SHIELD = The outer braid of audio or RF coaxial cable, or the aluminum

case enclosing a coil or transformer.The metal case of a transceiver also

performs an important RF shielding function.The shield blocks or protects a

coil from the effect of nearby objects that would change its inductance. The

shielding on cable prevents the inner wire from radiating (RF) or from picking

up stray radiation such as AC hum.

SQUELCH = means literally, to subdue utterly or crushingly! In radio

communication, usually VHF and UHF, squelch is the circuitry needed to

subdue (mute) the background noise until a detected signal "breaks" the

squelch.

SUPERHET = A receiver design that converts the incoming desired

frequency to a lower Intermediate Frequency (IF) where most of the gain

and bandpass characteristics reside.

TOROID = A style of making coils or inductors where the insulated wire is

threaded ("wound") around a metallic form shaped like a doughnut. This

style of coil making generally eliminates any need for additional shielding

which may be needed to make the coil's inductance immune to the presence

of other nearby components or objects with metallic content.

TRIMMER = either a capacitor or resistor, miniature and variable, intended

to permit exact, final adjustment of circuit values.

TX = Abbreviation for transmit, transmitter, transmitting.

T-R = Abbreviation for "Transmit-Receive Switching", which can be

accomplished by manual switches, relays or solid-state devices such as the

PIN diodes used in the FX transceivers.

UNLOCK, unlocked = refers to the condition in a PLL (phased locked loop)

where one or more elements of the loop become defective or incorrect,

preventing the phase detector from supplying the correct control voltage to

the oscillator for the intended frequency of operation.

VARACTOR = a diode whose capacitance can be varied in step by the

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Ramsey Electronics FZ-146 Specifications Page 44

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