Kenwood ag203 电路图.pdf

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1、A G - 2 D 3 CR Oscillator INSTRUCTION MANUAL RadioFans.CN 收音机爱 好者资料库 CONTENTS Features 3 Specifications 4 Circuit Description 6 Panel Controls and Their Functions 8 Operating Instructions 10 Applications . . . . . . 12 Maintenance 15 Adjustment 16 Caution 17 Parts List ; 18 PC Board 21 Schematic Dia

2、gram 22 RadioFans.CN 收音机爱 好者资料库 Features * All solid state circuitry insures extreme high stability, minimum warm-up time and less power consumption. * High reliability with adoption of direct coupled circuits throughout the entire stage. * Compact styling with vertical type panel for easy operation

3、. * Frequency dial scale calibrated with single-scale graduations for frequency range of 10Hz to 1 MHz selectable in 5 ranges. * High output design; more than 7 V rms at no load and more than 3.5V rms at 6 0 0 n . Output level is fully adjustable with a 10dB-step, 6 range attenuator and a level adju

4、ster. * L o w output impedance of 6 0 0 a . T h e attenuator provides accuracy of 1.0dB at 8 0 0 o load. * Sine and square waves easily available. * Synchronizing input terminal. * Extremely high stability against variation of power source voltage. 3 RadioFans.CN 收音机爱 好者资料库 Specifications Sine W a v

5、 e Characteristics Square Wave Characteristics Externa! Synchronization Characteristics Stability against power source voltage variation (with respect to variation of 100V 10%) 4 Frequency range: x 1 range; 1 0 H z - 100Hz x 10 range; 100Hz - 1kHz x 100 range; 1kHz - 10kHz x 1k range; 10kHz - 100kHz

6、 x 10k range; 1 0 0 k H z - tfVIHz Frequency accuracy: (3% + 1 Hz) Output voltages (no load I: 7 V rms or more Frequency characteristic: 10Hz - 1 MHz, 0.5dB (reference freq: 1kHz) Distortion factor: 400Hz - 20kHz, 0 . 1 % or less 1 0 0 H z - 100kHz, 0.3% or less (x 10 range for 100Hz) 50Hz - 200kHz,

7、 0.5% or less 20Hz - 500kHz, 1%or less 10Hz - 1MHz, 1.5% or less Output voltage (no load): 10V p-p or more Sag: 5% or less (at 50Hz) Rise and fall times: 200ns or I ess Overshoot: 2% or less (at 1 kHz, max. output) Duty ratio: 50% 5 % (at 1 kHz, max. output) . Synchronizing range: 1%/V Sta. allowabl

8、e Input 10V rms ltae: input Itnpedanee: Approx. 1 0 k o Output impedance: BOOo 10% Output attenuator: OdB, - 1 0 d B , - 2 0 d B , - 3 0 d B , - 4 0 d B and - 5 0 d B in 6 steps (accuracy: 1dB at 600a load) Frequency drift: Within 0.5% Output voltage variation: Within 0.5dB Operating temperature: 0

9、- 50C (relative humidity: Less than 90%) Power requirement: A C 100V (120V, 2 2 0 V or 2 4 0 V h 50 - 60Hz Power consumption: 5 watts External view: See Fig. 2 on page 9 Dimensions: Casing; 128(W) x 238(D) x 190(H) mm Overall (including knobs); 1 3 0 ( W ) x 2 6 8 ( D ) x 2 1 5 ( H ) mm 5 Weight: 2.

10、9 kg Accessories: Power cord 1) Output cord: one red and black test cord with basket clip and banana plug Banana plug; red (1) and black (1) Fuse; 0 . 1 2 5 A (2) and 0.2A (2) Instruction manual (1) Circuit Description 1 t Summary When reading the following descriptions, refer to the block diagram F

11、ig. 1J and the schematic diagram. The sine-wave signal generated by the Wien bridge oscillator circuit is fed through the W A V E F O R M select- tor switch set at the v position to the O U T P U T con- trol, by means of which it is adjusted to any desired voltage. Sf the W A V E F O R M switch Is I

12、n the_n_ position, the sine-wave signal Is shaped into the square wave and the voltage is also adjusted by the O U T P U T control. The signal voltage thus adjusted is applied to the output circuit, where Its impedance is appropriately converted, and then delivered through an output attenu- ator to

13、the output terminal. T h e attenuator provides selectable attenuations of GdB t h o u g h - 5 0 d B in 10dB steps at 6 0 0 n of output impedance. 2. Wiert Bredge Oscillator Circuit The WiPfi bridge oscillator circuit elements consist of the resistance elements, which may be switched over for 5 range

14、s by the F R E Q . R A N G E switch, and the variable capacitor controlled by the F R E Q U E N C Y dial. These elements provide means to vary the oscillating frequency continuously over 10 times its frequency on one range, thus determining any desired frequency within the entire frequency range fro

15、m 10Hz to 1MHz. The amplifier circuit for the oscillator circuit is put ge. e f i p i o n g D ? Qpl! cjj IL *, fh Ui r 1 -. i * h i - = the d = * btaoir u * y:,c v c , i :Y q; The * btPJ . D L J W 0 L P r M i, o T* , , pJem.nt - r t : nsi s roz T-, ou ptt v o r e fa J 11 prn /- h,n i - C3t , ?; whil

16、e ii aso fe; 1 Odd* vv, p o a . amplitude. 3, Square Wave Shaping Circuit The square wave shaping circuit is a khmidt-trigger circuit in which the sine wave signal from the oscillator circuit is shaped into a square wave. It is composed of an emitter coupled Schmidt-trigger circuit and a buffer ampl

17、ifier, thus providing sufficient rising and falling characteristics. 4., Output Circuit The output circuit converts the impedance of signal from the O U T P U T control and feeds the signal to the output attenuator at a low impedance. It is a S E P P - O C L circuit employing complementary transisto

18、rs to provide sufficiently low output impedance characteristics over the range from D C to 1MHz. 6 5. Output Attenuator The 6-position output attenuator selects attenuations of OdB to - 5 0 d B m 10dB steps. A t the OdB position with the O U T P U T control turned fully clockwise, the output voltage

19、 (sine wave at no-load time) is more than 7 V rms. The output impedance Is rated for 6 0 0 a and the at- tenuation accuracy is as high as 1 .OdB at a 8 0 0 o load. 6. Power SuppSy The power supply circuit is powered by A C 1 0 0 V , 120V or 2 2 0 V ) and delivers DC22Vsufficiently stabilized by larg

20、e capacity smoothing capacitors (2200MF x 2) and a voltage stabilizer. Wien bridge oscillator circuit E X T . S Y N C Square wave shaping circuit Output level control + DC22V- -DC22V Power supply . unit OUT P U T AC I 00V / 120V/220V /240V .50/60HZ F i g . 1 B l o c k Diagram 7 Selector- switch Outp

21、ut circuit Output attenuator Panel Controls and Their Functions The table below describes the functions of panel controls. Refer to the panel diagram on page 9. FRONT PANEL 1. This lamp (light emitting diode) lights when P O W E R switch (2) is O N . 2. P O W E R Pushbutton type switch turns on the

22、power when pressed. 3. A T T E N U A T O R 6-position output attenuator selects attenuations of OdB to - 5 0 d B in 10dB steps. 4. O U T P U T Output terminal used for both sine wave and square wave. T h e marking indicates G N D (case grounded). 5. W A V E F O R M Output waveform selector switch. W

23、hen pressed to V , output signal is sine wave. When pressed to - T L the signal is square wave. 6. F R E Q . R A N G E Oscillating frequency range selector switch which selects the ranges in 5 steps as follows: x 1 10Hz - 100Hz x 10 1 0 0 H z - 1kHz x 100 1 kHz - 10kHz x 1k 1 0 k H z - 100kHz x 10k

24、1 0 0 k H z - 1MHz 7. A M P L I T U D E Amplitude adjuster to continuously vary the amplitude of output voltage. 8. F R E Q U E N C Y D I A L This dial adjusts oscillating frequencies. Frequen- cies can be read by multiplying the reading on the dial scale by magnification of F R E Q . R A N G E , 9.

25、 D I A L S C A L E This dial is calibrated with graduations of 10100 to indicate oscillating frequencies. 10. D I A L P O I N T E R This pointer indicates frequencies on the dial scale. 8 REAR.PANEL- . 1 1 . S Y N C External synchronizing signal input terminals for G N D for connection of synchroniz

26、ing signal to A G - 2 0 3 . 12. F U S E Fuse for power supply. 13. A C C O N N E C T O R For connection of the supplied A C connector. 14. P O W E R V O L T A G E S E L E C T O R This selector is preset to 240V position. A C power of 100V, 120V or 2 2 0 V may be used by changing the position of the

27、selector. Front panel Rear panel FIG. 2 Operating Instructions 1. Start-up First check that the fuse (12) and the power voltage selector (14) are in the normal positions, then connect the supplied A C power cord to your A C outlet. Press the power switch (2) and the pilot lamp (1) will light indicat

28、ing that the unit is ready for operation. Allow 2 or 3 minutes for the unit to warm up so that it is stabilized. 2. Waveform Selection Press the W A V E F O R M switch (5) to the V posi- tion to obtain sine waves. Press the switch to the X L position for square waves. 3. Frequency Selection First se

29、t the F R E Q . R A N G E switch (6) to the desired range, then set the frequency dial (8) so that the dial pointer (10) indicates your frequency. Example: Suppose you want to select a frequency of 1.5kHz, then proceed as follows: 1. Set F R E Q R A N G E switch (6) to x 100. 2. By using the frequen

30、cy dial, set the dial pointer (10) ro 1 5 on the dial scale. The frequency thus selected is: 15 x 100 = 1500(Hz) = 1.5(kHz) 4. Adjustment of Output Voltage T h e output voltage from O U T P U T terminal (4), be it sine wave or square wave, can be continuously varied by A M P L I T U D E (7) and step

31、ped down by A T T E N U A - T O R (3). Example: T o adjust output voltage to 10mV rms, proceed as follows: 1. Connect a voltmeter capable of meas- uring A C 1 V rms to O U T P U T terminal (4). 2. Set A T T E N U A T O R (3) to OdB and then adjust A M P L I T U D E (7) until the voltmeter indicates

32、1V rms. A voltage of 1V rms will appear at O U T P U T terminal (4). 3. Set A T T E N U A T O R (3) to - 4 0 d B . T h e voltmeter indicates about 0 V , while a voltage of 1 0 m V rms appears at O U T P U T terminal (4). 5. Use of Synchronizing Input Terminal By applying an external sine wave signal

33、 to S Y N C ter- minal (11), the oscillating frequency of A G - 2 0 3 can be synchronized to the external signal. T h e synchronizing range is increased in proportion as the input voltage is increased as shown in Fig. 3, indicating that the synchro- nizing range is about 1 % per input voltage of 1V.

34、 Example: Suppose that the input signal voltage is 1V rms and the oscillating frequency of A G - 2 0 3 is between 9 9 0 H z and 1010Hz 10 ( 1 k H z 1 k H z x 1%/V x I V = 1 k H z 1 k H z x 0 . 0 1 ) , v the frequency can be synchronized with 1kHz of the input signal. Note that too high a synchronizi

35、ng signal voltage will affect the amplitude and distortion factor, and care must therefore be taken when the signal voltage is higher than 3 V rms. Also, note that if the synchronizing signal is largely deviated from the frequency of A G - 2 0 3 , the synchronization is pulled out which affects the

36、distor- tion factor. It is therefore advisable that the oscillating frequency be first synchronized with a low input signal voltage (less than 1 V rms) and then the voltage be increased. F i g . 3 11 Oscillating frequency deviation (%) Output level (dB) Distortion factor %) Synchronizing range Lxter

37、nal synchronizing input voltage ,(V rms) Output voltage variation External synchronizing input voltage( V rms) Output signal distortion Externa! synchronizing input voltage(V rms) Applications 1. Using as Sine Wave Oscillator A G - 2 0 3 can be used as a sine wave oscillator as out- lined below. 1.1

38、 Since the unit features low distortion factor, it can be used for measurement of distortion charateristic of amplifier. 1.2 Since the unit features wide bandwidth, it can be used for measurement of frequency charac- teristic of amplifier. 1.3 The built-in high accuracy attenuator permits measuremen

39、t of amplifier gain. 1.4 C a n be used as a signalsource of impedance bridge. 2. Measurement of Amplifier Gain A n example of measurement of amplifier gain is described below. First connect A G - 2 0 3 , amplifier to be tested and A C volt-meter as shown in Fig. 4. meter to A G - 2 0 3 to measure th

40、e output voltage. Note that the use of A T T E N U A T O R (3) eliminates the need for connecting a high sensitivity volt- meter, If A T T E N U A T O R (3) is set to OdB and the voltmeter indicates 2 V , it means that the input voltage of the amplifier is 50dB below 2V. There- fore, the gain obtain

41、ed is as follows; 50dB + 2 0 og10-L d B = 5 Q d B - 6dB = 44dB 3. Measurement of Phase Characteristic Connect A G - 2 0 3 and an oscilloscope to the amplifier to be tested as shown in Fig. 5. If there is no phase shift about the output signal of the amplifier, the oscilloscope will display a straigh

42、t fine as shown in Fig. 5 A . If the 1. Adjust A T T E N U A T O R (3) and A M P L I T U D E (7) so that A C voIt-meter indicates the rated output (supposed to be 1V in this example) of the amplifier. T o facilitate the measurement, it is advisable to set A T T E N U A T O R (3) as low as possible.

43、Assume that A T T E N U A T O R (3) is set - 5 0 d B for the rated output. 2. Disconnect the amplifier and connect the A C volt- A G - 2 0 3 OUT P U T AC voltmeter F I G . 4 Amplifier under test AG-203 Amplifier under test Oscilloscope F i g . 5 M e a s u r e m e n t of P h a s e C h a r a c t e r i

44、 s t i c No amplitude distortion Amplitude distortion on both sides straight line o n the oscilloscope is curved at its top and bottom sections as shown in Fig. 5 B , it indicates that the output signal of amplifier is suffering from an amplitude distortion. In this case, reduce the output level of

45、A G - 2 0 3 a little to vary the frequency. This causes the straight line on the oscilloscope to expand gradually to turn into an ellipse. By utilizing the configuration of this ellipse, the phase shift can be calculated as follows: First, measure the maximum horizontal deflection and suppose that t

46、his deflection is X and that the section at which the ellipse crosses the horizontal axis is x , as shown in Fig. 6. A n d , the phase shift angle e is given by the following. Find e from the table of trigonometric functions and the value obtained gives the angle of phase shift. 4. Using as Square W

47、ave Oscillator A G -203features excellent rising and falling character- istics (120 ns as standard characteristic). It has no coupling capacitors in the output stage, so the sag (de- flection of top section) is as low as 5% at 50Hz. By applying such a good square wave to an amplifier input, various

48、characteristics of amplifier can be observed on an oscilloscope. T o test an amplifier, proceed as follows: 13 F i g . 6 C h e c k o f P h a s e S h i f t A n g l e 1. Connect A G - 2 0 3 , an amplifier to be tested and an oscilloscope as shown in Fig. 7. 2. Press W A V E F O R M (5) to the _TL position to obtain square waves of appropriate frequency and amplitude. 3. During the test, change the frequency as necessary. The relationship betwee