8
FIG. 1-BASIC SPECTAUM ANALYZER. The first function generator produces a linear ramp waveform (either a triangle or a sawtooth) V1• That is applied to the FM input of the second function generator to produce an FM sinusoid, V2, which is applied to the inputs of a filler or amplifier. The output, V3, is applied to the vertical amplifier of an oscilloscope, the time base of which is set to external sweep. The ramp V1 is applied to the horizontal amplifier, and the amplitude spectrum appears on the CAT. If VI' the output of the first func- tion generator, is a l-kHz triangle wave applied to the FM input of the second function generator, and if V 2 is a IO-kHz sine wave, then V 2 would be an FM sinusoid. Varying the fre- quency of VI varies the rate of change about the carrier frequency, and vary- ing the amplitude of VI varies the deviation from that center frequency, or the modulation index. However, while the FM waveform is needed to generate a spectrum, it isn't the spec- trum itself. If the l-kHz triangle wave is ap- <D CXl <D (J) m "O -1 m s: lJl m :Il OSCILLOSCOPE WITHTIME BASE ON EX- TERMINAL SWEEP II~I V3i :1: HORIZ VERT + You can build a 20-600MHz spectrum monitor FILTER OR AMP plied to the horizontal oscilIoscope inputs, the CRT beam wilI sweep out a horizontal line along the x-axis of the graticule. Varying the amplitude of VI control s the length of the line on the oscilIoscope screen. By making the frequency of VI high enough and experimenting with its amplitude, you can make the beam occupy the whole length of the bottom of the graticule, and make its retrace com- pletely invisible. Now take any audio filter or ampli- fier, a piece of stereo equipment, for example. If you apply V 2 to this filter V2 + FM SINE WAVE GENERATOR ® + FM TRIANGLE WAVE GENERATOR + Vl FRED BAUMGARTNER Spectrum analyzer theory The function of a spectrum ana- lyzer is to tune across a controlIed frequency range and display RF am- plitude versus frequency on a CRT. Frequency increases from left to right (the + x-direction), while amplitude increases from bottom to top (the + y- direction). The signal being analyzed is applied to the vertical amplifier of an oscilIoscope, and the horizontal amplifier is driven by a linear ramp like a triangle or sawtooth. The simplest spectrum analyzer re- quires an oscilIoscope and two sine! square!triangle function generators, connected as shown in Fig. 1. The oscilloscope time base is set for exter- nal sweep, and the scope's horizontal input is grounded. The beam is posi- tioned at the bottom center of grati- cule, which wilI be the origino WE !-lAVE ALL, AT ONE TIME OR ANOT!-IER, needed some of the capabilities that a spectrum analyzer offers. Unfor- tunately, sophisticated analyzers can cost more than a new car! So most of us have managed to live without the benefits that those instruments offer. After all, a meter, oscilloscope, fre- quency counter, and RF pro be can actually give quite a bit of information about a signal environment. But none of those instruments can depict the total spectral content cIearIy and un- ambiguously, and give you informa- tion on modulation or spurs. The solution is the spectrum monitor presented here. It doesn't have the frequency or amplitude reso- lution 01' a professional version, but it costs onJy around $200, and you'lI be able to view the 20-600 MHz range and compare relati ve levels. The spectrum monitor has two op- erating modes; you can use it to either visualIy display an amplitude spec- trum on an oscilIoscope, or as a re- ceiver to help identify FM signals. 33

Spectrum Monitor

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Page 1: Spectrum  Monitor

FIG. 1-BASIC SPECTAUM ANALYZER. The first function generator produces a linearramp waveform (either a triangle or a sawtooth) V1• That is applied to the FM input of thesecond function generator to produce an FM sinusoid, V2, which is applied to the inputsof a filler or amplifier. The output, V3, is applied to the vertical amplifier of an oscilloscope,the time base of which is set to external sweep. The ramp V1 is applied to the horizontalamplifier, and the amplitude spectrum appears on the CAT.

If VI' the output of the first func­tion generator, is a l-kHz trianglewave applied to the FM input of thesecond function generator, and if V2

is a IO-kHz sine wave, then V2 wouldbe an FM sinusoid. Varying the fre­quency of VI varies the rate of changeabout the carrier frequency, and vary­ing the amplitude of VI varies thedeviation from that center frequency,or the modulation index. However,while the FM waveform is needed to

generate a spectrum, it isn't the spec­trum itself.

If the l-kHz triangle wave is ap-

<DCXl

<D

(J)m"O

-1ms:lJlm:Il

OSCILLOSCOPE

WITHTIME

BASE ON EX­

TERMINAL SWEEP

II~IV3i :1: HORIZ

VERT +

You can build a20-600MHz

spectrum monitor

FILTER

OR AMP

plied to the horizontal oscilIoscopeinputs, the CRT beam wilI sweep outa horizontal line along the x-axis ofthe graticule. Varying the amplitudeof VI control s the length of the line onthe oscilIoscope screen. By makingthe frequency of VI high enough andexperimenting with its amplitude,you can make the beam occupy thewhole length of the bottom of thegraticule, and make its retrace com­pletely invisible.

Now take any audio filter or ampli­fier, a piece of stereo equipment, forexample. If you apply V 2 to this filter

V2+

FM SINE

WAVE GENERATOR

®+FM

TRIANGLE WAVE

GENERATOR

+Vl

FRED BAUMGARTNER

Spectrum analyzer theoryThe function of a spectrum ana­

lyzer is to tune across a controlIedfrequency range and display RF am­plitude versus frequency on a CRT.Frequency increases from left to right(the + x-direction), while amplitudeincreases from bottom to top (the + y­direction). The signal being analyzedis applied to the vertical amplifier ofan oscilIoscope, and the horizontalamplifier is driven by a linear ramplike a triangle or sawtooth.

The simplest spectrum analyzer re­quires an oscilIoscope and two sine!square!triangle function generators,connected as shown in Fig. 1. Theoscilloscope time base is set for exter­nal sweep, and the scope's horizontalinput is grounded. The beam is posi­tioned at the bottom center of grati­cule, which wilI be the origino

WE !-lAVE ALL, AT ONE TIME OR ANOT!-IER,

needed some of the capabilities that aspectrum analyzer offers. Unfor­tunately, sophisticated analyzers cancost more than a new car! So most of

us have managed to live without thebenefits that those instruments offer.

After all, a meter, oscilloscope, fre­quency counter, and RF pro be canactually give quite a bit of informationabout a signal environment. But noneof those instruments can depict thetotal spectral content cIearIy and un­ambiguously, and give you informa­tion on modulation or spurs.

The solution is the spectrummonitor presented here. It doesn'thave the frequency or amplitude reso­lution 01' a professional version, but itcosts onJy around $200, and you'lI beable to view the 20-600 MHz rangeand compare relati ve levels.

The spectrum monitor has two op­erating modes; you can use it to eithervisualIy display an amplitude spec­trum on an oscilIoscope, or as a re­ceiver to help identify FM signals.

33

Page 2: Spectrum  Monitor

PIXAT612.75MHz

SNDAT608.25MHz

DOWN-CONVERTER SECTION I L1

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PRESCALE(PS\SUPPLY+5V

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ZENITH S..x SERIES 17S-22928 TUNERlCONVERTER

the FM signal coming out as a func­tion of frequency. The voltage gain indecibels (AdB) as a function of fre­quency is equal to 20 times thebase-lO logarithm (log) of the ratio ofV3 to V2. Or:

AdB = 20 x loglO(V 3/V 1)'

curve with valleys and plateaus in itsshape. That is the amplitude frequen­cy-response ofthe filter or amplifier, avisual depiction of the amplitude of

or amplifier, and apply the filter oramplifier's output V 3 to the os­cilloscope's vertical amplifier, youshould see some smooth continuous

~ FIG. 2- TUNER/CONVERTER BLOCK DIAGRAM. The Zenith SX Series 175-2292A tunerlz converter is the heart of the project. It accepts RF signals from about 55-553 MHz and~ downconverts them to a standard 63-MHz constant-levellF.f-()W...JW

ÓCi«a:

34

Page 3: Spectrum  Monitor

J4HORIZ'

OUT

AUDIO 6 S2

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AC OPERATION

R32

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VERTICAL

OVERSHOOT SUPPRESSION2-POLE

LOW PASS FILTER (LPF)

,

R25

VERT

OFFSET

SAWTOOTH

WAVE SHAPING/

PULSE PROCESSING

BUFFER/

IMPEDANCE

CONVERTER

12VAC

(SEE TEXT)

HORIZ

OSC/UNE

SYNCHRONIZER

C26

TUNING

CAPACITOR

+10V(IC1)

+5V (IC2)

+10V (IC3)

DETECTOR/

DEMODULATOR

IF OUT

68MHzJ2 PL2

'i: +9VJ

- (OPTIONAL1 Ni-Cd_ BATTERIES)

J

: +9V

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.¡.

R18CENTER

FREQ

555

ASTABLE VOLTAGE

TRIPLER AND CLlPPER

L+10V(IC3)

RF IN

55.25-553.25

MHz

4ANT +10V

(IC1¡

PL3 ~ ~F~ TÚNER

FIG. 3-SPECTRUM MONITOR BLOCK DIAGRAM.

Note that AdB is a function of fre­quency, not time. That ratio (or thelog of it) is called the amplitude spec­trum of a signal, and is a plot of how afilter, amplifier, or any other elec­tronic component responds to varia­tions in frequency.

Tuner/converter principiesThe previous example was at audio

frequencies, while the spectrummonitor discussed here works at RE

Certain variations in the previous ideaare necessary to make spectral analy­sis practical at such frequencies. AnRF spectrum analyzer ordinarily usesa sawtooth wave rather than a trianglewave as the horizontal scanning wave­form, sihce that waveshape is easier togenerate at RE AIso, rather than gen­erating an FM sinusoid as the drivingwaveform which generates the spec­tral response, most spectrum ana­Iyzers use a tuned receiver to scanover a frequency range.

The real object behind using a tri­angle or sawtooth waveform is thattheir slopes are essentially linear, so

the resulting FM generatÍon is also.The minimum frequency for a tri­angular waveform corresponds to thenegative-most point of each cycle,and the maximum frequency to itspositive-most point. The frequencyrange for a sawtooth waveform goesfrom minimum to maximum duringits long rise time, with a sharp retraceat the end of a cycle. In both cases, theduration of each ramp must occupythe entire length of the x-axis of theCRT graticule.

The spectrum monitor uses a com­mercially available tuner/converternormally found in TV's, VCR's, andcable converters to down-convert nor­mal RF to a standard 63-MHz con­stant-Ievel IF, tunable over the desiredfrequency range. As mentioned ear­lier, there are two distinct operatingmodes; you can either observe a sig­nal in sweep mode regardless of mod­ulation type, or you can demodulateFM using the internal FM receiver IC.

There are all sorts of ways to obtaintuner/converters from cable convert­ers and TV or VCR front ends; the rest

of the parts are readily available. Ifyou use the Zenith tuner discussedhere, enough information is providedregarding its internal circuitry and pi­nouts so that you shouldn'thave anyreal difficulty. Without proper testgear and some reasonable familiaritywith RF electronics, you shouldn'tuse a different model.

The spectrum monitor can be madeto work with a wide variety of tuners,including those that use bipolar sup­plies or need negative tuning volt­ages. The important tuner charac­teristic to look for is continuous

tuning. Many tuners also have bandswitching, like those for TV's andVCR's, although they require a switchto supply band-change voltages.AIso, there may be gaps in frequencycoverage, like between channels 5and 6, or between the VHF and UHFbands. Cable converters use those

spaces, so a cable-ready set or cabletuner probably won't have that prob­lem. However, they may not tune all ofthe UHF band (approximately470-850 MHz). Ideally, the tunershould reach at least 550 or 600 MHz.

(f)m"1J-1ms:lJlm:IJ

35

Page 4: Spectrum  Monitor

RADIO-ELECTRONICS

-

HORIZOUT

J4

18+lOVGNO SUPPR15 (1C3)

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Page 5: Spectrum  Monitor

Third, you'lI want a usable outputlE TV Channel 3 (63 MHz) is popu­lar, but Channel 4 (69 MHz) is suit­able and within the range of the

~ project. Also, you'lI want relativelyz stabk gain characteristics and few im­~ ages or spurs.}:) Some adjustment of the spectrum~ monitor may be necessary for useÓ with yourtuner. Automatic Gain Con­o trol (AGC) voltages can be brought<a: out to a front panel control to set RF

gain, or tied to a voltage representingfull gain. Measuring the local os­cillator output with a frequency coun­ter will enable you to calculate thecenter frequency.

Zenith SX tuner/converterThe Zenith SX series tuner/con­

verter (part number 175-2292A) usedin the prototype is representative of asuitable tuner; a block diagram isshown in Fig. 2. It can be bought with

the kit described in the Parts List, ordirectIy from Zenith Corp. It containsboth up- and down-converter sec­tions, and fits into a 4.25- x 2.78- x1.05-inch aluminum shell with one"F" -type and two RCA-type jacks.

The "F"-typejack (15) is the RFIN,

with a frequency range of55.25-553.25 MHz. One RCA-typejack (J2) is the 63-MHz IFOUT, and thesecond (17) is the PRESCALE output,

continued on page 64

Page 6: Spectrum  Monitor

l' 2 INCHES ' ILF TRANSMITTER FOIL PATTERN. LF CONVERTER FOIL PATTERN.

SPECTRUM MONITOR

continued from page 42which isn't used here.

There are two PC-board plugs sup­plied with the tuner. One is a two-pinversion, PL5, used for A/B SWITCH,

which along with C1 is unused. Theother is a Single-Inline-Pin (SIP)plug, PL6, which connects to most ofthe pinouts. Pin 1 (black) of PL2 isground, pin 2 (green) is the SECOND

LOCAL OSCILLATOR + 12-volt supply(unused), pin 3 (orange) is the UP­

CONVEIUER + 12-voltsupply, pin 4 (vi­olet) is the FIRST LOCAL-OSCILLATOR

TUNING VOLTAGE, and pin 5 (yellow) isthe AUTOMATI~ FREQUENCY CONTROL

(AFC) voltage for tuning the secondlocal oscillator over the range517-617 MHz. Pin 6 is not wired.

Even though the up- and down­converter supplies are labeled as nom­inally needing + 12 volts, + 10 voltsproved to be adequate. The AFC po­tential on pin 5 of PL2 should nomi­nally be + 2.5 volts, to keep thesecond local oscillator at 567 MHz.Enough information is provided to letyou look into suitable replacements ifyou can't get this version, or want toexperiment with others.

Spectrum monitor operationThe block diagram of the spectrum

monitor is shown in Fig. 3. It canoperate using either 12-volts AC or

~ + 12-volts DC, and provision is alsoz made for optional Ni-Cd batteries. An~ RF signal over the frequency ranget> 55.25-553.25 MHz is applied to the~ Zenith tuner via J5. The tuner willwÓ down-convert to a 63-MHz IF, theo center frequency being adjusted using~ R18, and the sweep width using R20;

64

the IF exits the tuner via 12. It is thenfed to an FM receiver IC that acts asdetector/demodulator. The input reso­nant frequency of the IC is adjustedusing trimmer capacitor C26.

The output of the detector/demod­ulator IC is applied simultaneously toa discrete NPN transistor preamplifierand an op-amp buffer/impedancecon verter. The preamplifier outputgoes to an IC power amplifier andspeaker, the volume being adjustedusing R12. This is the FM-receiveraudio output, letting you listen to FMbroadcast stations, TV audio, two­way FM communications, etc.

The buffer/impedance converter ispart of the vertical output section, andis followed by a two-pole low-passfilter which suppresses any signal am­plitude overshoots, preventing thespectrum monitor from forcing theoscilloscope beam off the graticule.That's followed by a vertical offsetclipper and oscilloscope driver ampli­fier, which is adjusted using R4. Theoutput of this amplifier is fed to theVEIU OUT jack 13.

Note that S2 feeds power to eitherthe audio amplifier for receiver opera­tion, or IC7 for sweep operation inspectrum monitor mode. The two op­erating modes are mutually exclusive;you can't use the monitor to simulta­neously observe a region of the RFspectrum, and listen to whatever sta­tion is at the center frequency of thedisplay. However, it is a simple matterto switch between modes.

The horizontal circuitry beginswith a horizontal oscillator, whichalso acts as a line-voltage syn­chronizer. When the spectrummonitor is powered by 6O-Hz AC, the12-volts AC from the secondary ofTl

is coupled into the horizontal os­cillator, locking it to the 6O-Hzpower­line frequency automatically. When12-volts DC is applied directly to 11,synchronization to 60 Hz becomesimpossible, so the horizontal os­cillator will be free running.

The horizontal-oscillator waveformthen passes through a network thatgenerates the sawtooth waveformused for horizontal scan/retrace. Thatsawtooth is amplified by a horizontaldriver and appears at HORIZ OUT jackJ4. The sweep frequency is adjustedusing R32, but the adjustment iseffective only when the spectrummonitor is operated using AC.

Circuit descriptionThe complete schematic of the

spectrum monitor is shown in Fig. 4.The spectrum monitor uses 12-voltsAC or + 12-voltsDC, allowing opera­tion from a car battery, or a plug-in 12­volt AC adapter. It also can operate offof a Ni-Cd power pack.

Diode DI is the power rectifier for12-volts AC, D2 and resistor R1 pro­vide a charging path for the Ni-Cdcells, and SI is an SPST ON/OFFswitch. While a full-wave rectifierwould be much easier to filter, itwould prevent AC/DC compatibility.The filter is composed of R2 and ca­pacitors C1 and C2. AIso, C3 samplesAC to synchronize the sweep os­cillator to 60 Hz. The three voltageregulators provide regulated + 10­volts DC to the tuner, and + 5-voltsDC to the sweep circuits. TheTDA7000 receiver uses +4.5 volts;the drop across D3 provides +4.3volts, which is adequate.

While the 555 timer (IC5) is con­continued on page 92

Page 7: Spectrum  Monitor

SPECTRUM MONITOR

continued from page 64

figured as an astable, its real purposeis to function as an additional voltagesource. It works in conjunction withT2, a 3:1 toroidal auto-transformer, toprovide the tuning voltage. Mosttuner/converters need 0-25 volts forfull-range control. The primary of T2is supplied by the + 10 volts fromIC3, and the 143.056-kHz oscillationsuperposes ari additional 20 volts,producing 30 volts across C31. Theduty cycle is very low to conservepower. Next, D5, a 25-volt Zener,clamps and regulates the tuning volt­age, and R18 controls the tuning volt­age for the first local oscillator in thetuner.

For tuners requiring negative ormultiple voltages, T2 will have to bemodified. For a different maximumamplitude required, change the ratioof T2, and for a negative voltage,reverse D4 and D5 and also the non­tap terminal s on the auto-transformer.This will force the auto-transformer togenerate negative-going pulses,which will be superposed upon the

+ lO-volts DC. Reversing D4 and D5allows current to be passed in the re­verse direction, and the Zener voltageof D5 could be changed if needed.The horizontal sweep generator pro­duces both sawtooth and pulse wave­forms, and can be externallysynchronized.

The purpose of D9, 010, and R33is to allow the negative and positiveslopes to be set independently. Notethat R33 is in series with D9, but thatthere's no comparable resistor in se­ries with DIO. Thus, R33 extends theduration of the sawtooth waveformup-ramp so the CRT beam fits on thehorizontal axis ofthe graticule. Then,DIO permits a steep, rapid discharge,minimizing the sawtooth waveformfall time and permitting fast horizon­tal retrace. Sweep-frequency potenti­ometer R32 allows the time constantto be varied.

Zener-diodes 07 and D8 clamp theoutput of the oscillations from IC7-c,D7 the negative-going direction, andD8 the positive-going direction.Then, IC7-d buffers the sawtoothgenerated across C39, and IC7-cswitches C39 from charge to di s­charge based on the feedback through

R34. Finally, D6 routes the blanking/sync pulse to the vertical section(IC7-a and IC7-b) for vertical retrace.Note that D6 may need to be shortedor left out for faster vertical retrace,although some oscilloscopes will ex­perience vertical overshoot as a result.You'll have to experiment with what­ever oscilloscope you use, in order todecide.

True "Z" -axis control (blanking orbrightness) is difficult to obtain onmany oscilloscopes. If yours permitsexternal blanking control, it's avail­able as a positive pulse from pin 8 ofIC7-c. This pulse drives the CRTbeam vertically off the screen duringretrace and turns the vertical amplifieroff, preventing retrace from beingseen.

The Signetics TDA7000, IC6, is acomplete FM receiver on a chip. Thetank LI-C26 for the Volt­age-Controlled Oscillator (VCO) onpin 6 is the only RF adjustment. OnlyL2, C15, and C16 are required on IC5as external components to create theRF input filter and perform matching.If the IF is 45 MHz, the value of Llmay need to be increased. By alteringLl, any IF from 30-110 MHz may be

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SPEAKER CONTROL

#260-210

PANEL •• 1

Panel wi!h 50 wall L-pads .lor tweeler and midrangeand buill-in LEO powermeler. 5-" 2 112- 100

wattnDiODanl1ab1e $1290$14.S0 •#260-235 (l-5) (6-up)

12" POLY WOOFERSuper duty, 40 01. magneL100 wallB RMS. 145 waIlB

mazo 4 and 8 ohm COIl\PllI­ible (6 ohm). :r voice coi!.la=25 Hz. QTS=.l66,

en VAS~ 10.8 cu 11.

S:;! Response: 25-1800 Hz. NelZ wei¡¡ht 9 lbs. Pioneer

~ #A3OGU40-5ID

1- #290 5 $36_SO&3 -12 (l-3)..J

g IE;P~~ ==~I~a=01>o484CII

FAX: 513-222-4644

92

Page 8: Spectrum  Monitor

ASSEMBLE YOUR OWNCOMPUTER FOR LE$$

uscd. It's also possible to similarlyadapt L2.

Thc TOA 7000 reduces the received

signal deviation from ± 75 kHz to± 15 kHz (suitable for the internal IFof 70 kHz), using an internal Fre­quency (no! phase) Locked Loop(FLL). The TOA 7000 greatly sim­plifies the circuitry for many tunedcircuits and filters, and neither needsnor uses AGC. In its place, a sampleof IF limiter voltage is fed back to theIF L1MITER CAPACITOR input (pin 12),after being buffered and amplified byIC7 -a. The gain of IC7 -a is controlledby R22. The prototype used 500 K forR22, but the gain can be varied byusing a potentiometer.

The positive signal portion of the IFenvelope is amplified by IC7-b to pro­duce the vertical drive. Potentiometer

R25 sets the base line to "rectify" thesignal from IC7-a. Between IC7-aand IC7-b, a two-pole low-pass filtersmoothes DC ripple and reduces ver­tical overshoots. Also, IC7-a convertsthe high-impedance receiver sectionAGC, where the RF level is derived,to something low enough for properfilter design, while also providingsome gain. Ovcrall, IC7-a and IC7-b

provide a gain of about 40.The tuner is the heart of the spec­

trum monitor. It accepts the RF IN (15)and produces a 63-MHz IF OUT (12).The FIRST LOCAL-OSCILLATOR TUNING

VOLTAGE controls the first local os­cillator. Remember that there are two

operating modes, FM receiver andspectrum monitor. In the former, thetuning voltage is steady DC and isdetermined by center frequency po­tentiometer R18. In the latter, the tun­ing voltage is swept.

Sweep-width potentiometer R20control s the tuner sweep-voltage andhow much of the spectrum is dis­played. The SPDT switch S2 selectsbetween modes, not merely by select­ing between the outputs for each withboth sections (IC4 and IC7) operatingsimultaneously, but actually switchespower between them, saving powerand avoiding any coupling problems.

Well, we regret that we must stophere for now, as our space has come toan end. However, next month we willcontinue with complete constructiondetails, including PC Service. We'llal so show you how to troubleshootany problems. We will then, ofcourse, show you how to use it. R-E

IBM XT 10 MHz Compatible Kit... ".$37984.77/10 MHz Motherboard

82561<8 RAM (6401<8 max)8150W Power Supply8 Floppy Disk Controller

80ne 51/4, 3601<8 Drive8 MonoGraphics Card w/ P8101 Key Keyboard8Case (3LED,2Button,Key)812' Amber Mono Monitor81nstallation Gulde & Manual

IBM AT 12 MHz Compatible Kit...." $70588/12 MHz Motherboard

85121<8 RAM (4 MB max)8200W Power Supply8 Floppy Disk Controller80ne 51/4' 1.2 MB Drive8 MonoGraphics Card w/ P8101 Key Keyboard8Case (3LED,2Button,Key)812' Amber Mono Monitor81nstallalion Guide & Manual

Display Upgrade: Hard Drive Option:CGA Package $200 20MB w/CTRL XT-$275 AT-$315EGA Package $455 30MB w/CTRL XT-$31 O AT-$41 O

VGA Package $500 40MB w/CTRL XT-$390 AT-$415MS-DOS with GWBASIC $75

AII Componants Fully Tested Belore ShipVISA & M/C subjecl lo 3% surchargePrice & Quantity subjecl to change without prior notice15% Restocking Fee on AlIllems

JINCO COMPUTERS INC.5122 WALNUT GROVE AVE.

SAN GABRIEL, eA 91776Tel: (818) 309-1108Fax: (818) 309-1107

IBM, XT, AT are registered trademarks 01In1ernational Business Machine.

CIRCLE 184 ON FREE INFORMATION CARO

CIlm"tJ-lms:IIIm:D

KIT ASSEMBLED$59.50 $69.50

12.9212.9214.76

$ 5.197.1515.0051916.6320.156.259.2221.4571.50

$82.5012.65 9.2218.0012.0015.00

25.0020.00

35.0024.15 33.00

46.2038.45 19.4626.80

38.80

. ·62.00

150.00

83.00noo19.80 1S.5015.50

DESCRIPTION0-15V 2A RegulatedDC power Supply A A A * .0-15V 5A RegulaledDC PowerSupply A.0-30V 3A RegulatedDC power Supply A ..0-50V 3A RegulatedDC power Supply A A

Battery Flourescent Light Driyer ..••..........Electronic Touch Switch ..••.....ELectronic Lotto .•.............•Multí-Functional Control Switch ADigital Clock w/timer'" .....Color Led Audio Leyel Meter •••.Electronic Shock'" _ .

High Precisíon Sound Control Switch A .V Shape Color Led Leyel Meter"''' ....3 Channel Color Light Controler .•..•.•••. *Stereo Loudspeaker Protector .ir.. ••

FM Wireless Microphone .•.....AC/DC Quartz Digital Clock ASound/Touch Control Switch'" ...Infrared Remate Control Unit .•..•..•.Infrared Remote Control Unit .•..•..•..BarIDot Leyel Meter .•..•.........31/2 Digital Panel Meter'" .20 Steps Bar/oot Audio Leyel Display •.•...............Superior Electronic Roulette .•..•.7 Bands Graphíc Equalizer •.•.•. * .4 Channel Professional Color Light Controller * .AudioJVideo Surroul1d Sound Processor .•..•.•. * ..LCO Thermometer Clock w/in-outdoor sensor * _ .LCo Thermometer Clock wl F & C measurement * .Parrot Talking Clock * .Mynah Talking Clock *

TY~IATV-7TV-8TV-IIATV-12ATV-13TV-14TV-18TV-20TV-HBTV-25TV-35TV-3bTV-38TV-41MKlllTV-4IMKVTV-42TV-OTV-45TV-47SM-222SM-328SM-H3T-IT-2# 8501# 8504

70.00

7S.00

80.58

116.8090.00

43.38110.00

$ 40.0016.5817.71

$ 5.076.90

11.208.20

30.0011.8412.6531.2SlS.0050.0035.5029.5059.9516.6268.0060.9245.9448.0059.6973.7093.30

48.9033.2086.00

MATCHINGTA-2800, TA-377A .TA-3221,TA-323A, TA-377A .TA-802, TA-820A, TA-1500, TA-120,TA-800, TA-l000A .TA-477, TA-800, TA-1500, TA-l000A .

DESCRIPTION3" x 12"x r4" x 16" x 8"4" x 19" x 11.5"

5" x 19" x 11.5"

1W Míní-AmpJifier A. .6W Mini-Amplifier .•..12W Mjni-Amplifier .••.............Stereo Pre-Amp. w/magnetic mico amp .6. ..Digital Voice Recorder A A:.. .Multí-Purpose Melody Generator AMulti-Purpose Melody Generator.lr. ..Class HA" Main Power Mono Amp. A A .....30W Multi-Purpose Single Channel Amp . .4. .60W Slereo Power Booster A.a. * .50W -+- 50W le Stereo Amp. w/led level display'" .HQ30W + 30W StereoAmp. A .FET Stereo Pre-Amp. A lA ¿*40W Salid State Mono Amp . .A .....120W Mosfet Power Mono Amp. 4. 4. ...80W + BOW De pre-Maín & Power Amp .• A. .BOW + BOW DC Stereo Main Power Amp. A.&. .60W + 60W OCLDC Pre-MainStereoAmp. AA100W Class "A" Maín Power Mono Amp. AA.. .1OOW x 2 Class"A" DL Stereo Pre-Maín Amp. A. &. A. .Electronic Echo & Reyelatíon Amp. A. A A * .Ha Pre-Amp. w!10 band graphíc equalízer •......Hi-FI Bj-Fet Pre-Amp. w/3 way Ion e control AA.Stereo Slmulator .•..•...................300W HO Hí-Fi Power Mono Amp ..•••.•. A. .

LG-1925

MODEllG-1273lG-lb84LG-1924

TA-OOITA-006TA-007TA-IOTA-28MK2TA-50A/BTA-50CTA-120MK2TA-300TA-302TA-3221TA-323ATA-377ATA-400TA-477TA-800TA-802TA-820ATA-IOOOATA-1500TA-2400ATA-2500TA-2800TA-3000TA-3600

MODEL DESCRIPTION MATCHING PIECE# 001 56V CTto 60V CT6A TA-800, TA-802, TA-820A, TA-l OOOA,TA-1500 $25.00# 002 72V CT3A TR-503, TA-3221,TA-323A, TA-400 .. _ 19.00 MODEl DESCRIPTION KIT ASSEMBlED# 003 80V CT6A TA-477 24.00 SM-43 3V, Multi-Functional Led D P.M. AA * $34.50 $ 43.00# 004 48V CT6A TA-120 19.00 SM-48 4V, Hi-PrecisionDP.M. AAA* _. _ 38.00 48.00#005 52VCT3A TR-355B. 12.00 SM-48A 4V,Hi-PrecisionD.P.M.w/stndrdcaseAAA* , .. 41.20 52.00# 006 36V CT5A TR-355A 13.60 SM-IOO 150MC Digital FrequencyCounter* 90.00# 007 112V CT8A TA-3600 38.00 FCIOOOA 1 GHzFrequencyCounter* __.. __.. __ 182.00

- WC ACCEPT MAJOR CREDIT CAROS, MONEY ORDERS ANO CHECKS. - BUSINESS & SHOWROOM HOURS: (PACIFIC TIME) MON.- FRI.: 9:30 AM.- 5:00 P.M., SAL 10:00 AM.- 5:00 P.M.TERMS $10.00 MIN. ORDER • $20 MIN. CHARGE CARO ORDER. WE SHIP UPS GROUND • ADD 10% OF TOTAL aRDER (MIN. $3.00) FOR SHIPPING OUTSIDE USA,

~D~Rf8~;,1~~~ l3~JOJZT ~~A~~rN'~~lJv~f~80T ~g?lg~'.00J~~'i:L ~gn~R~OUNSS~Bc¡,~LF'6RCM6~~!~~Fc¿E~RStÓ~~ TAX • ALL MERCHANDISE SUBJECT TO PRIOR SALEJ 1""[ pgYAIcI. IllJ el ~• ." •• J ."J IU:fI::f J. JII .:11:12.,./f,/C r~~·f J~/~ J 11~ D~:(.J'~"...JC~~l:".".,/C,,:,./~ •• ,,:[,r.

CIRCLE 93 ON FREE INFORMATION CARO 93