function generator operation manual...function generator, which can directly generate sine,...
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FUNCTION GENERATOR
OPERATION MANUAL
INDEX
1. Introduction ………………………………………… (3)
2. Specifications ………………………………………… (3)
3. Working Theory ……………………………………… (7)
4. Structure ……………………………………………… (8)
5. Operation & Maintenance …………………………… (9)
6. Accessories ………………………………………… (14)
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This instrument is a highly stable, multipurpose, broad bandwidth
function generator, which can directly generate Sine, Triangle,
Square, Ramp, Pulse waveforms as well as Linear & Logarithm
Sweep signals. Application of Single-chip-machine intelligently
controls all of the functions, displays and indicators, which allow
users to know about the working status of the instrument easily
and accurately.
1. Specifications
1.1 Frequency Range: 0.6Hz-6MHz
1.2 Waveform:
Sine, Triangle, Square, Positive & Negative Ramp,
Positive & Negative Pulse. Symmetry of Ramp and Pulse
is variable within 80:20 (1Hz~100kHz)
1.3 Sine Waveform:
1) Distortion: ≤1% (0.1Hz~100kHz)
2) Frequency Response: ≤±0.5dB(0.1Hz~100KHz);
≤±1dB(3MHz);
≤±2dB(6MHz);
1.4 Rising/Falling Edge of Square Waveform: ≤50ns
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1.5 TTL Output:
1) Higher Level ≥2.4V, Lower Level ≤0.4V, capable
of driving 20 TTL loads.
2) Rising time: ≤30ns
1.6 Output:
1) Impedance: 50Ω±10%
2) Output Amplitude: ≥20Vp-p (open circuit),
3) Output Attenuator: 20dB, 40dB, 60dB
4) DC Offset: 0 ~±10V adjustable
5) Display Error of Amplitude: ±10% ±2 digits
(output level higher that 1/10 of full scale)
1.7 Power Output:
1) Amplitude: ≥20p-p
2) Output power: Max. 5W
1.8 VCF Input:
1) Max. Voltage: -5V~0V ±10%
2) Max. Control rate: 1000:1
3) Frequency: DC~1kHz
1.9 Amplitude Modulation:
1) Carrier Bandwidth:
2) Modulation Freq.: 400Hz (INT), 0~1MHz (EXT)
3) Modulation Depth: 0~85%
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1.10 Frequency Modulation:
1) Deviation: 0 ~ 10%
2) Modulation Freq.: 400Hz(INT), 0 ~ 20kHz (EXT)
3) Distortion: ≤ 1.5% ( fc=500kHz, fm=1kHz, 10%)
1.11 Sweep
1) Sweep mode: Linear, Logarithmic.
2) Sweep time: 10ms~5s
3) Sweep rate: 1000:1
4) Output Amplitude: 7Vp-p
5) Output Impedance: 600Ω
1.12 Frequency Counter:
1) Measuring Range: 1Hz-20MHz
2) Input Impedance: 1MΩ / 20pF
3) Sensitivity: 10mVrms
4) Max Input: 150V AC+DC (with attenuator)
5) Input attenuator: 20dB
6) Measuring Error: not more than 3×10-5 ±1 digit
1.13 Power Supply
1) Voltage: AC 220V ± 10%
2) Frequency: 50Hz±2Hz
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1.14 Operating Ambient:
1) Temperature: 0°C~40°C
2) Humidity: ≤RH 90%
3) Atmospheric Pressure: 86kPa~104kPa
1.15 Dimension (mm): 290L × 260W × 90H
1.16 Weight: 3kg
2. Working Theory
Figure 1
2.1 Waveform Generator Circuit
This segment is consisted of MAX038 Function Generator,
Frequency & Duty Rate control circuits. Waveforms are
selected by SCM.
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2.2 SCM (Single-chip-machine) Circuit
This segment is consisted of SCM 89C52, Panel Input,
Frequency & Amplitude Display and Output & Indicator
circuits. The main jobs are: Control waveform of output
signal; Test and display the frequency of output or external
input signal; Display amplitude of output waveform.
2.3 Frequency Counting Circuit:
It is consisted of Broad-banded Amplifier and
Square-waveform Regulator, which external signal will go
through.
2.4 Power Amplifier
In order to insure the stability and high slew rate, dual
channel power amplifier is employed. The entire amplifier is
with the characteristic of phase inversion.
2.5 FM Mode
When SWP/FM switch being pressed down and MOD
switch is pulled up, a 1KHz modulation signal which
generated by RC oscillator is applied to VCF end.
2.6 Power Supply
Four sets of power supply, ±23V/±15V/±5V/+5 are
employed. ±23V is used for Amplifier. ±15V and ±5V are
used for Waveform Generator. +5V is mainly for SCM circuit.
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3. Structure
This instrument has an all-metal frame and cover, plastic
front panel with a elegant and small-sized appearance. Most
of the components (including switches and knobs) are fixed
on two PCBs. All adjustable components are located at an
easy-to-adjust position. Only to unscrew the back panel and
remove the cover up and down when the instrument need to
be adjusted or repaired.
4. Operation and Maintenance
4.1 Symbols and functions in front panel and rear panel:
See Table 1, Figure 2 and Figure 3.
Figure 2
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Table 1
NO SYMBOL DESCRIPTION OPERATION
1 POWER Power Switch Push down, power on
2 △ Frequency Range
Selection
Press the key, the multiples of freq. will be changed
from low to high. Collaborate with Knob “19” to set
output frequency.
3 ▽ Frequency Range
Selection
Press the key, the multiples of freq. will be changed
from high to low. Collaborate with Knob “19” to set
output frequency.
4 Waveform Selection
Press the key to change output waveform. Work
with knob “17” and key “18”, polarity of ramp and
pulse can be selected.
5 DC OFFSET DC Offset Press button. Indicator lights when the function is
activated.
6 DC Offset Knob DC output can be adjusted with from
-10V~+10V(Output waveform is 5Vp-p)
7 MODE
Linear/Logarithmic
/External Sweep
selection
Sweep mode will change in sequence each time the
button is pressed.
8 SPEED Sweep Speed Adjust the knob to change sweep speed.
9 Output Attenuator Press the button to set attenuation among 0, 20dB,
40dB and 60dB. Indicators light respectively.
10 OUTPUT Voltage Output Output terminal of waveforms, max. output 20Vp-p
with impedance of 50Ω.
11 AM/FM AM/FM Adjustment
Activate modulation mode with button “24”. If the
knob is Pull-out position, the instrument is in AM
mode, modulation depth can b adjusted with the
knob. If the knob is Push-in position, the instrument
is FM mode, frequency deviation can be adjusted
with the knob.
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12 AMPLITUDE
Output Amplitude
Adjustment
Waveform Inversion
Work with button “9” to adjust amplitude of output
waveforms.
13 INPUT Counter Input
Terminal
To test the frequency of an external signal, connect
the signal to this terminal.
14
EXT
ATT20dB
LPF
Selector of
INT/EXT signal,
20dB Attenuator and
Low-Pass Filter
When external signal is selected and the signal is too
strong, press the key, 20dB attenuator is activated
with the indicator lit. Press the key again, LPF
indicator lights(with attenuator, cutoff freq. 100kHz)
About 20 seconds after no signal is detected, “0”
will be displayed.
15 WIDTH Sweep Width Use the knob to adjust sweep width when the
instrument is in sweep mode.
16 Amplitude Display
Display peak to peak value of output signal (open
circuit). If a 50Ω load is connected, actual value on
the load is 1/2 of that is displayed. If desired output
amplitude is lower than 1/10 of max. value when
amplitude knob is fully turned, connecting an extra
attenuator is advised. If the instrument is working in
AM mode, displayed amplitude is an Un-cal value.
17 SYMMETRY Symmetry Adjusting Symmetry can be adjusted from 20:80 to 80:20.
18 Symmetry
Activating Key
Press the key to activate symmetry adjusting knob.
19 Frequency
Adjustment
Turn the knob CW, output frequency is increased
and vice versa.
20 Frequency Display
Display the frequency of output signal or external
input signal. Indicator “GATE” blinks when counter
is working well. If input frequency over 20MHz,
indicator “OV.FL” will be on. Hz and kHz indicate
what units of frequency would be at the moment
when one of them turns on.
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4.2 Symbols and functions in rear panel:
Figure 3
21 Power Socket AC 220V/0.5A fuse or AC110V/1A fuse.
22 Line Voltage Selection 110V/220V switching.
23 VCF IN/EXT MOD IN/EXT
SWP IN Terminal
a) Input terminal of Voltage-Control-Frequency,
input voltage range 0~-5V.
b) Input terminal of External Modulation signal.
c) Input terminal of External Sweep signal.
A sweep signal is generated while frequency
vary along input control signal.
24 MOD ON/OFF switch of AM/FM,
INT/EXT modulation selection.
25 TTL OUT Output terminal of TTL pulse,
with impedance of 50Ω.
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4.3 Service and Calibration
This instrument can be operated continuously in proper
ambient, but you are advised to calibrate it every three
months. Calibration procedure is as:
1) Sine Distortion Calibrating:
Turn Amplitude Adjusting Knob to its max, select sine
waveform output and set frequency at 1kHz. Connect this
signal to a distortion meter. Adjust RP102 to have distortion
match technical requirement.
2) Output Amplitude Calibrating:
Set the instrument in the same working status as 1), connect
the signal to an oscilloscope. With observing peak-peak
value of the output signal, adjust RP601 to have the output
amplitude match technical requirement.
3) Frequency Calibrating:
Set frequency counter at “EXT”, connect a 10MHz signal of
standard oscillator to the input terminal. Adjust C607 to get
standard 9999.9kHz on the LED display. Set the amplitude
of the standard signal to 100mVrms, adjust RP401 to have
9999.9kHz stably displayed on LED.
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4.4 Trouble Shooting
Sufficient knowledge is needed when you are going to fix
problems on this instrument. Locate the problem area in
PCB by with observing the phenomenon, visual inspection
is suggested in first place, and then check the PCB in static
and dynamic mode. Replace the component which is found
broken.
5. Accessories
Operation Manual 1copy
Power Cord 1pc
Test Lead(50Ω) 1pc
BNC Cord 1pc
Fuse (0.3A) 2pcs
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