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SCORPION ELECTRONICS

PHASE SHIFT KEYED MODULATOR

LAB EQUIPMENTS

PROJECTS

UPS

1

#1,12thEast Strt, Ka!ara"ar Naar, Th$r%&a'!$(%r, Ch''a$) *+++1- Ph. + ) 2/20/

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CIRCUIT OF PSK MODULATOR

Phase Shift Keyed modulator is used widely in binary data communication systems.

At the transmitter the binary signals are used to generate a continuous phase shifted carrier signal with a

mark or logic-1 representing 1800phase shift from the carrier signal ! space or logic "0 state represented

by 00phase shift or same as carrier signal.

#0#$ is used to generate the s%uare wa&e carrier signal. 'he transistor ()*#+ is used as in&erter to generate

1800phase shift signal on the arri&al of logic data at PSK input.

,

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Th +*B IC

'he #0#$( )S /) is an outstandingly useful P. /ts built-in ) can be &oltage-scanned

through a million-to-one fre%uency range and has a top-end fre%uency limit in e2cess of 134. 'he 5ig.

Shows the outline and pin notations of the de&ice which is housed in a 1$ pin 6/ Package. 'his figure also

shows the internal block diagram of the #0#$( and the basic e2ternal connections of its integral ).

'he #0#$( houses two different types of phase comparator plus an e2cellent ) a 4ener diode

and a source follower buffer stage. Phase comparator1 7P)1 is a simple 9:-; type and has a good noise

re and 1#. /t has only a narrow

capture-fre%uency range. Phase comparator , 7P), is an edge-triggered logic?bistable type with a three-

state output and can be dri&en by grossly non-symmetrical wa&eforms on pins > and 1#. /t has a &ery wide

capture-fre%uency range but fairly poor noise re

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'he #0#$( @s ) is a wide-range type with a ma2imum operating fre%uency in e2cees of 134.

'he &oltage on pin determines the fre%uency by the capacitor &alue between pins $ and + and by the

&alues of ;1 ;,. ;, enables the minimum operating fre%uency to be preset and can be eliminated in many

applications. 'he ) generates a symmetrical s%uare-wa&e output which appears in pin #.

'he /)Bs pin ) "input terminal has a near infinite input impedance and can be dri&en from a

high-impedance source. 'he internal source-follower enables the pin &oltage to be e2ternally monitored

without loading this source. /nhibit terminal * of the /) is normally tied to ss to enable both the ) and

the source follower. (oth of these de&ices are disabled when a logic-1 is applied to pin *. the /)Bs internal

4ener diode has a nominal &alue of * can be used to pro&ide supply regulation if re%uired.

O%t%t 3a&45r!

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