Analog 1 kHz Generator
Sine Waves with Low Distortion
Component list
Component List
Resistors
Unless otherwise specified:
MELF 0204 or thin film SMD 1206, 1%
R1 = 47 Ω
R2, R5, R8, R9, R11, R15, R17, R18 = 3k3
R3 = 200 Ω, multi-turn trim pot, vertical, RM 1/10‘‘
R4 = 150 Ω
R6, R7, R10, R12, R16, R19 = 100 Ω*
R12, R16, R19 = 100 Ω
R13 = 10 k, potentiometer, linear
R14 = optional*
R20 = 820 Ω, SMD 0603
R21 = 100 Ω, SMD 0603
R22, R24, R26 = 56 kΩ, SMD 0603
R23, R35, R36 = 8k2, SMD 0603
R25 = 100 kΩ, multi-turn trim pot, vertical, RM 1/10‘‘
R27, R28 = 4k7, SMD 0603
R29, R30, R31, R32 = 10 kΩ, SMD 0603
R33 = 2k2, SMD 0603
R34 = 5k1, SMD 0603
Capacitors
C1, C6 = optional*, COG, SMD 0603
C2, C3, C8= 47 nF, film, RM 2/10‘‘ (alternative to C4, C5, C7)*
C4, C5, C7 = 47 n, COG, SMD0805 (alternative to C2, C3, C8)*
C9, C15, C17…C20, C22, C24…C27 = 100 nF, X7R, SMD 0603
C10, C11 = 22 µF / 16 V, SMD 1206
C12 = 2µ2 / 16 V, SMD 1206
C13 = 47 pF, COG, SMD 0603
C14, C16, C21, C23 = 22 µF / 25 V, Tantal Elko, SMC-B
Semiconductors
LED1, LED2 = LED, SMD 0805
D1, D2 = BAV199, SOT23
D3, D5 = 1N4004
D4, D6 = SK34, DO214AC
T1 = 2N3904, SOT23
IC1, IC3 = OPA2211*, SOIC8
IC2, IC4 = TL072, SOIC8
IC5 = 78L12, TO92
IC6 = 79L12, TO92
IC7 = NSL-32SR3*
VR1 = TL431, TO92
Miscellaneous
JP1, JP2 = 2-pin header, LP 1/10‘‘
JP12 = 4-pin header, LP 1/10‘‘
JP13 = 3-pin header, LP 1/10‘‘
Circuit board 230704-01
Knob for pot R13
Audio sockets*
* See text
Discussion (0 comments)
F1Andy 7 months ago
EN0170521ID 7 months ago
EN0170521ID 7 months ago
Short of using an infinite number of voltage levels, you can't avoid these harmonics whenever you generate analogue waveforms by digital means, whereas analogue generation of sinusoids can be achieved directly by suitable circuitry whose output changes continuously with time without discrete "jumps" in voltage, therefore the harmonic content is very greatly reduced, typically by up to 100 times compared with a DDS generator!
Chris Williams
EN0170521ID 7 months ago
Thank you for providing the layout files!
Chris Williams
Blue bird 6 months ago
Since your E-mail address in your article doesn't seem to work, please see my feedback below.
In your article "Analog 1Khz-generator" you have used a precision rectifier. For the explanation there is a reference to a TI design.
Here I notice that there is probably an issue in the circuit of your article. R32 should be connected with D2. Please see correction schematic picture
When simulating in LTSPICE as is in the article the rectifier behaves badly see simulation bad picture
When correcting the schematic the simulation provides an OK rectifier see simulation corrected picture
If the PCB is designed according to the schematic, this also should be reviewed.
Thanks,
Gino
simulation-bad.png (65kb)
simulation-corrected.png (59kb)
TL072.zip (1kb)
Taetz 6 months ago
my EMail address in the english article is correct and working. Try it again, please.
You are right, there is a bug in the schematics. It was redrawn by the Elektor team. The EAGLE schematics is correct and so is the PCB.
Alfred
dementor-1987 5 months ago