Kenwood AG-203 User manual

AG-2D3
CR Oscillator
INSTRUCTION MANUAL

CONTENTS
Features 3
Specifications 4
CircuitDescription6
Panel ControlsandTheirFunctions8
OperatingInstructions• • • • 10
Applications......12
Maintenance15
Adjustment • • 16
Caution17
Parts List; 18
PC Board21
Schematic Diagram22

Features
* Allsolidstatecircuitryinsuresextremehighstability,minimumwarm-up
timeand less powerconsumption.
* Highreliabilitywithadoptionofdirectcoupledcircuitsthroughout
theentirestage.
* Compactstylingwithverticaltypepanelfor easy operation.
* Frequencydial scale calibratedwithsingle-scalegraduationsforfrequency
range of10Hzto 1 MHzselectablein5 ranges.
* High output design;morethan7Vrmsatnoloadandmorethan3.5V
rms at 600n. Outputlevelisfullyadjustablewitha 10dB-step,6 range
attenuatoranda leveladjuster.
* Low output impedanceof 600a. Theattenuatorprovides accuracy of
± 1.0dBat800oload.
* Sine andsquare waves easily available.
* Synchronizinginputterminal.
* Extremelyhighstabilityagainstvariationofpowersourcevoltage.
3

Specifications
[SineWaveCharacteristics]
[Square Wave Characteristics]
[Externa! SynchronizationCharacteristics]
[Stability against power source voltage
variation (with respectto variation of
100V± 10%)]
4
Frequencyrange:
x 1 range;10Hz-100Hz
x 10range;100Hz- 1kHz
x 100range;1kHz- 10kHz
x 1krange;10kHz- 100kHz
x 10krange;100kHz-tfVIHz
Frequencyaccuracy: ±(3%+
1 Hz)
Output voltages(no load I: 7Vrmsor
more
Frequencycharacteristic: 10Hz- 1 MHz,± 0.5dB
(referencefreq:1kHz)
Distortion factor:
400Hz- 20kHz,0.1%or less
100Hz-100kHz,0.3%or
less (x10rangefor100Hz)
50Hz- 200kHz,0.5%or less
20Hz- 500kHz,1%or less
10Hz- 1MHz,1.5%or less
Output voltage (noload): 10Vp-por more
Sag:
5% or less
(at50Hz)
Rise and fall times: 200nsorI
ess
Overshoot:
2% or less (at 1 kHz,max.
output)
Duty ratio:
50% ±5% (at
1 kHz,max.
output) .
Synchronizingrange: ±1%/V
S¥ta.allowable Input 10Vrms
¥©lta§e:
input Itnpedanee:
Approx. 10ko
Output impedance: BOOo±10%
Output attenuator:
OdB, -10dB,-20dB,-30dB,
-40dBand-50dBin6 steps
(accuracy:±1dBat600a
load)
Frequency drift:
Within ±0.5%
Output voltage variation:
Within ±0.5dB
Operatingtemperature:
0- 50°C(relative humidity:
Less than 90%)
Power requirement:
AC 100V(120V,220Vor
240Vh50- 60Hz
Powerconsumption:
5 watts
Externalview: See Fig.2 onpage9
Dimensions:
Casing; 128(W)x 238(D)x
190(H)mm
Overall (including knobs);
130(W)x268(D)x215(H)mm

5
Weight:
2.9 kg
Accessories:
Power cord{1)
Outputcord:oneredand
black testcord with basket
clipandbananaplug
Banana plug;red(1)and
black (1)
Fuse; 0.125 A (2)and0.2A(2)
Instructionmanual(1)

Circuit Description
1 t> Summary
Whenreading the following descriptions,refer to
theblockdiagram{Fig. 1Jand the schematicdiagram.
The sine-wavesignalgenerated bythe Wienbridge
oscillatorcircuit isfed through the WAVE FORM select-
torswitch setatthe '"v" position tothe OUTPUT con-
trol, by means of which itis adjusted toany desired
voltage.
Sf the WAVE FORM switch IsIn the"_n_"position, the
sine-wave signal Is shaped into the squarewave andthe
voltage is alsoadjusted bythe OUTPUT control.
The signalvoltagethusadjusted is applied tothe
output circuit,where Its impedance is appropriately
converted, and thendelivered through an output attenu-
ator tothe output terminal. The attenuatorprovides
selectable attenuations of GdB though -50dB in10dB
steps at 600n of output impedance.
2. WiertBredgeOscillatorCircuit
TheWiPfi bridgeoscillatorcircuitelementsconsist
of the resistanceelements,which maybe switchedover
for 5 ranges bythe FREQ. RANGE switch, andthe
variablecapacitorcontrolled bythe FREQUENCY dial.
These elementsprovidemeans to vary the oscillating
frequency continuouslyover 10 times its frequency on
onerange,thusdetermining any desiredfrequency
within the entirefrequencyrange from 10Hz to 1MHz.
The amplifiercircuit forthe oscillatorcircuit is
put ^ge. efipio^ng D? Q~pl!cjj<' ••''^IL *, fh^ Uir<
sf3ge s a high , ipu hrije^ar^r * tu\ >1["'-.i * h i - =
the d •'•'=•*btaoir u * y\^:,c \v '<c' ,'i:Y'< "o5
V'
d'C'jj' vv3ji PHP uan$6i&^ fasris i. t*';'r , n-ofi•>
q; The * btP'J. DLJ^ W 0 ~ L Pr ~M i, 'o' "T* , ~ ,
pJem..nt - r ^ t': nsi s ro'z
T'-~,
ou 'pt't vo^re fa J ^ ¥ 11 pr^n/->h,n>~ i -
C3"€t,?; while ii a»so fe;1 Odd* vv,^ poa.'>
amplitude.
3, SquareWaveShapingCircuit
The squarewaveshapingcircuit isa >khmidt-trigger
circuit in which the sinewavesignal from the oscillator
circuit is shaped into a square wave. Itis composed ofan
emittercoupledSchmidt-triggercircuit anda buffer
amplifier,thus providing sufficientrising and falling
characteristics.
4., Output Circuit
The output circuitconverts the impedance of signal
from the OUTPUT control and feeds the signal tothe
output attenuator ata low impedance. Itisa SEPP-OCL
circuitemployingcomplementarytransistors to provide
sufficiently low output impedancecharacteristicsover
therange from DCto1MHz.
6

5. Output Attenuator
The 6-position output attenuatorselectsattenuations
ofOdBto-50dBm 10dBsteps.AttheOdBposition
with the OUTPUT controlturned fully clockwise,the
output voltage(sinewaveatno-loadtime)is more than
7V rms.
The output impedanceIsratedfor600aandtheat-
tenuationaccuracyisashighas±1.OdBata 800oload.
6. PowerSuppSy
The powersupplycircuitispoweredbyAC
100V, 120Vor220V)anddeliversDC±22Vsufficiently
stabilizedbylargecapacitysmoothingcapacitors
(2200MF x 2)anda voltagestabilizer.
Wien
bridge
oscillator
circuit
EXT.SYNC
Square
wave
shaping
circuit
Output
level
control
+ DC22V-
-DC22V •
Power
supply
.unit
OUT PUT
AC I 00V/ 120V/220V/240V
.50/60HZ
Fig. 1 Block Diagram
7
Selector-
switch
Output
circuit
Output
attenuator

Panel ControlsandTheirFunctions
The tablebelowdescribesthefunctionsofpanel
controls.Refertothepaneldiagramonpage9.
FRONT PANEL
1. Thislamp (light emitting diode)lightswhen
POWER switch(2)isON.
2. POWER
Pushbuttontypeswitchturnsonthepowerwhen
pressed.
3. ATTENUATOR
6-position output attenuatorselectsattenuations
ofOdBto-50dBin10dBsteps.
4. OUTPUT
Output terminalusedfor both sinewaveand
square wave.ThemarkingindicatesGND (case
grounded).
5. WAVE FORM
Output waveformselectorswitch.Whenpressed
to" V, output signalissinewave.Whenpressed
to "-TL" thesignalissquarewave.
6. FREQ. RANGE
Oscillatingfrequencyrangeselectorswitchwhich
selects therangesin5 stepsasfollows:
x 1 10Hz- 100Hz
x 10100Hz-1kHz
x 1001 kHz- 10kHz
x 1k10kHz-100kHz
x 10k100kHz-1MHz
7. AMPLITUDE
Amplitudeadjustertocontinuouslyvarythe
amplitudeof output voltage.
8. FREQUENCY DIAL
This dialadjustsoscillatingfrequencies.Frequen-
cies canbereadby multiplying thereadingonthe
dial scale bymagnificationof FREQ.RANGE,
9. DIAL SCALE
This dialiscalibrated with graduationsof10—100
toindicateoscillatingfrequencies.
10. DIAL POINTER
This pointer indicatesfrequenciesonthedial scale.
8

REAR.PANEL- ' ' .
11. SYNC
External synchronizingsignal input terminals
forGNDfor connection ofsynchronizingsignal
to AG-203.
12.FUSE
Fuse forpowersupply.
13. AC CONNECTOR
For connectionofthesuppliedACconnector.
14. POWER VOLTAGE SELECTOR •
This selectorispresetto240Vposition.ACpower
of100V,120Vor220Vmaybeusedbychanging
the position oftheselector.
Frontpanel
] Rearpanel
FIG. 2

OperatingInstructions
1. Start-up
First checkthatthefuse(12)andthepowervoltage
selector (14)areinthenormalpositions,thenconnect
thesuppliedACpowercordtoyourACoutlet. Press
thepowerswitch(2)andthe pilot lamp(1)will light
indicatingthattheunitisreadyforoperation.Allow
2 or3 minutesfortheunittowarmupsothatitis
stabilized.
2.WaveformSelection
Press the WAVE FORM switch(5)tothe"Vposi-
tion toobtainsine waves. Press theswitchtothe"XL"
positionforsquare waves.
3. FrequencySelection
First setthe FREQ.RANGE switch(6)tothedesired
range, thensetthefrequencydial(8)sothatthedial
pointer(10)indicatesyourfrequency.
Example: Supposeyouwanttoselecta frequency
of1.5kHz,thenproceedasfollows:
1. Set FREQ RANGE switch(6)tox 100.
2. Byusingthefrequencydial,setthe
dialpointer(10)ro"15"onthedial
scale.
The frequencythusselectedis:
15 x 100= 1500(Hz)= 1.5(kHz)
4. AdjustmentofOutputVoltage
The output voltagefrom OUTPUT terminal(4),be
itsinewaveorsquare wave, canbecontinuouslyvaried
by AMPLITUDE (7)andsteppeddownby ATTENUA-
TOR (3).
Example: Toadjust output voltageto10mVrms,
proceedasfollows:
1. Connecta voltmetercapableof meas-
uringAC1 V rmsto OUTPUT
terminal(4).
2. Set ATTENUATOR (3)toOdBand
thenadjust AMPLITUDE (7) until the
voltmeterindicates1Vrms.A voltage
of1Vrmswillappearat OUTPUT
terminal(4).
3. Set ATTENUATOR (3)to -40dB.
The voltmeterindicatesabout0V,
whilea voltageof10mVrmsappears
at OUTPUT terminal(4).
5. UseofSynchronizingInputTerminal
By applyinganexternalsinewavesignalto SYNC ter-
minal(11),theoscillatingfrequencyof AG-203 canbe
synchronized totheexternalsignal.Thesynchronizing
range isincreasedin proportion astheinputvoltageis
increased asshowninFig.3,indicatingthatthesynchro-
nizingrangeisabout±1%perinputvoltageof1V.
Example: Supposethattheinputsignalvoltageis
1V rmsandtheoscillatingfrequencyof
AG-203 isbetween990Hzand1010Hz
10