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µC makes inexpensive sine-wave generator : 12/17/98 EDN-Design Ideas
/ (Circuit / schematic design added 6/06) You can use A/D converters or
external, controllable oscillators to generate sine waves from low-power, low-cost
µCs. However, these methods add cost, reduce reliability, increase circuit and
software complexity, increase power consumption, and increase overall size.
Alternatively, and with just a few lines of code, most µCs can easily generate
multiple discrete sine waves. The example in Figure 1 uses a 68HC705J1A to generate
sine waves of 9 to 20 kHz. The circuit uses the µP’s square-wave output and switches
between multiple RC filters of varying cutoff frequencies to achieve outputs with
reasonable spectral purity.... |
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1KHz Sine Wave Generator: (Circuit added 9/04) |
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4 Transistor Tracking Transmitter: (Electronic Schematic / circuit
added 4/02) |
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4 Transistor Transmitter: (added 8/03) |
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68HC11 Synthesizes Accurate Sine Wave: 09/02/96 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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Amplitude Stable Oscillator has Low Distortion Low Cost: 11/09/00
EDN-Design Ideas / (added 10/06) / The multivibrator is a common circuit that consists
of an amplifier with both positive and negative feedback (Figure 1a). When the output
is positive, the positive input terminal equals ½V+, and the voltage at the negative
input terminal changes toward V+. When this voltage exceeds ½V+, the output voltage
rapidly changes to V–. The positive input terminal becomes ½V–, and the negative input
terminal changes toward V–. When the voltage at the negative input terminal is less
than ½V–, the process repeats (Figure 1b). For the multivibrator to work, the
bandwidth of the amplifier must be 10 times higher than the time constant of the
passive network, and consideration.... |
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AN-263: Sine Wave Generation Techniques: National Semiconductor -
Application Note (added 2/06) |
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AN-319: Simple Interface between D/A Converter and Microcomputer Leads to Programmable
Sine-Wave Oscillators: AN-319 - Analog Devices Application Notes
(Circuit / schematic design added 6/06) |
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Analog LED Bar VU Meter: The circuit was designed to work with an audio
power amplifier which operated off +18v-0v-18v power rails. The actual voltage used is
not too critical except that the feedback is referred to the LED chain which itself is
anchored to a +12v rail, hence the separate stabilizer .... (added 5/09) |
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Basic RF Oscillator #1: (Electronic Schematic / circuit added 4/02) |
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Circuit Generates Clean Sine Waves: 06/19/97 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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CMOS hex inverter generates Low distortion sine waves: 02/05/2004
EDN-Design Ideas In low-noise analog circuits, a high-gain amplifier serves at
the input to increase the SNR. The input signal level determines the input-stage gain;
low-level signals require the highest gain. It is also standard practice in low-noise
analog-signal processing to make the circuit's bandwidth as narrow as possible to pass
only the useful input-signal spectrum. (added 10/05) |
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Compensation Extends Oscillator's Range: 12/05/96 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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Crystal Filter yields Pure Sine Wave: 06/98 Intersol Application Note
# AN9815 / (added 6/03) |
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Current Feedback Amp yields Simple Oscillator: 06/08/95 EDN-Design
Ideas / (Electronic Circuit diagram added 03/03) |
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Current Feedback Amps Square Up Fast Signals: 06/23/94 EDN-Design
Ideas / (Electronic Circuit diagram added 03/03) Using current-feedback amplifiers to
convert signals from sine waves to square waves for DSP confers advantages over the
more common comparator approaches. Current-feedback amplifiers have wide bandwidths
and relatively small and constant propagation delays. These small, constant delays
help meet the setup-and-hold requirements of digital logic. Typically,
current-feedback amplifiers have delays from 1.1 to 5 nsec....
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Digital signal Controls sine generator: 05/15/03 EDN Design Ideas
/ (added 1/05) The circuit of Figure 1 produces an accurate,
variable-frequency sine wave for use as a general-purpose reference signal. It
includes an eighth-order elliptic, switched-capacitor lowpass filter, IC3, which uses
a 100-kHz square-wave clock signal that microcontroller IC2 generates. (Any other
convenient square-wave source is also acceptable.... |
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Digital Signal Processor (DSP) for Radio Communications: (Electronic
circuit added 7/03) |
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Digital Signals Produce Pure Sine Waves: 10/09/97 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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DTMF Coder Makes Low Cost Sine Wave Generator: 10/13/94 EDN-Design
Ideas / (Electronic Circuit diagram added 03/03) A telephone DTMF IC produces, by
design, two tones if you connect a single intersection of the IC's 4[x]4 keypad matrix
(Fig 1). (Telephones commonly have 3×4 keypads but, unknown to many people, the
applicable standard allows for a fourth row of four keys.) But, if you connect two key
inputs at once, the IC produces a single-frequency, low-distortion sine wave. Table 1
lists values for an HM9187 (Winbond Electronics, Santa Clara, CA, (408) 943-6666. (DI
#1592] ... |
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Easily Tuned Sine Wave Oscillators: National Semiconductor -
Application Note (added 2/06) |
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Few Extra Components Stabilize Oscillator: 02/15/96 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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Gates Provide Low Cost Sine Wave Generator: 08/15/97 EDN-Design Ideas
/ (Electronic Circuit diagram added 03/03) |
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LB-16: Easily Tuned Sine Wave Oscillators: National Semiconductor -
Application Note (added 2/06) |
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LC Oscillator has 1% THD: 03/31/94 EDN-Design Ideas / (added 03/03) At
the heart of many oscillators is a parallel-resonant LC tank circuit whose impedance
is infinite at the resonant frequency of 1/2[pi]ÖLC Hz. Infinite impedance implies an
absence of parallel damping resistance, so once an ideal tank circuit starts
oscillating, it should continue indefinitely. An actual tank circuit, of course, has
parasitic resistances that dissipate energy, causing the oscillations to die out. You
can counteract this effect by adding a "negative" resistance, which cancels the net
parallel parasitic resistance. Fig 1a's circuit uses a wideband transconductance
amplifier to synthesize negative resistance easily.... |
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Low Distortion Oscillator Starts Fast: 05/26/94 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) Unlike a Wien-bridge oscillator, the
phase-shift oscillator in Fig 1 starts up quickly. Also, the circuit does not require
that you adjust several trimming resistors just to tune the oscillator to a given
frequency. Experiments show that the circuit's total harmonic distortion (THD)
measures approximately 0.5% or less. Connecting the output of a bandpass stage to its
input via a phase inverter realizes a phase-shift oscillator. In practice, a
phase-shift oscillator also needs a limiter stage. Unfortunately, the limiter can
distort the output sine wave. Diodes D1 and D2 in the feedback loop of IC1A form a
limiter that does not distort.... |
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Low Frequency Sine Wave Generator: The two circuits below illustrate
generating low frequency sine waves by shifting the phase of the signal through an RC
network so that oscillation occurs where the total phase shift is360 degrees.
(Electronic circuit added 5/02) |
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Low-distortion Audio-range Oscillator: Generates very low-distortion
sine waves up to 1V RMS No thermistors required - No settling time (circuit design
added 3/05) |
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Negatrons Enrich Filter Oscillator Designs: 07/21/94 EDN-Design Ideas
/ (Electronic Circuit diagram added 03/03) The latest wave of high-performance op amps
allows you to incorporate "negatrons" (synthesized negative resistors) into your
oscillators and filters. Fig 1 shows the universal filter/oscillator circuit based on
a simulated lossy inductor and a negative resistance, which compensates the lossy
inductor. Note that the circuit has no physical inductors. The performance of this
circuit is very predictable and repeatable. Op-amp IC2 and its associated components
form a gyrator that simulates the inductance LEQ=C2R4R5. Paralleling LEQ with C1 forms
a parallel-resonant LC tank circuit. Op amp IC1 and its associated components form the
negatron that simulates a negative resistance, -(R1R3)/R2.... |
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OpAmp Oscillators Simplify RF Designs: 10/10/96 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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Oscillator Lowers Distortion and Phase Noise: 08/18/94 EDN-Design
Ideas / (Electronic Circuit diagram added 03/03) In addition to its normal role of
controlling oscillation frequency, the crystal in Fig 1 also acts as a high-Q,
self-tuned output filter, which rejects the noise and harmonics of its input voltage,
VB. The result is a clean output-frequency spectrum. With an output frequency of 10.7
MHz, second harmonic distortion is -76 dBc, and third-harmonic distortion is -72 dBc.
Other harmonics are less than 80 dBc, and output power is +7 dBm at 50 Ohms. C1 and R4
counterbalance the undesirable effects of the parallel capacitance CP of the crystal,
which represents a side path through which the highest harmonics of VB can reach the
output. ... |
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Programmable Oscillator uses digital potentiometers: 03/07/02 EDN
Design Ideas / (added 1/05) Digital potentiometers are versatile
devices; you can use them in many filtering and waveform-generation applications. This
Design Idea describes an oscillator in which setting the resistance of two digital
potentiometers independently programs the oscillation amplitude and frequency. Figure
1 shows a typical diode-stabilized Wien-bridge oscillator that generates accurate sine
waves fro... ... |
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Simple Circuit Generates Clean Sine Waves: 06/19/97 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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Simple Compensation Extends Oscillator's Range: 12/05/96 EDN-Design
Ideas / (Electronic Circuit diagram added 03/03) |
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Simple Interface between D/A Converter and Microcomputer Leads to Programmable
Sine-Wave Oscillators: AN-319 - Analog Devices Application Notes
(Circuit / schematic design added 6/06) |
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Simple sine synthesizer generates 19 kHz pilot tone for FM baseband signal:
04/14/05 EDN Design Ideas / (added 5/05) Low distortion, single-frequency
sine source for stereo FM. |
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Sine reference is synchronous with ac line: 02/15/00 EDN-Design Ideas
/ (added 2/06) |
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Sine Synthesizer Generates 19 Khz Pilot Tone for FM Baseband Signal:
04/14/05 EDN Design Ideas / (added 5/05) Low distortion, single-frequency
sine source for stereo FM. |
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Sine Wave Generation Techniques: National Semiconductor Application
Note 04-Nov-1995 (circuit / schematic added 2/03) |
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Sine Wave Generator: (Electronic circuit added 7/03) |
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Sine Wave Generator #2: (Electronic Schematic / circuit added 4/02) |
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Sine wave step up converter uses Class E concept: 02/17/05 EDN Design
Ideas / (circuit / schematic added 6/05) Many power applications ranging
from luminescent and fluorescent lighting to telephone-ringing voltage generators
require a more or less sinusoidal-drive voltage. These applications typically require
a waveform of only moderate quality, and its frequency isn't especially critical.
However, avoiding waveform discontinuities that cause unwanted current peaks,
excessive device dissipation, and EMC... |
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Sine/Cosine Wave Oscillator: (Electronic circuit added 7/03) |
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Sine-wave generator outputs precise periods: 04/26/01 EDN-Design Ideas
/ (added 2/06) |
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Spot-frequency Sine Wave Generator: 300Hz, 1KHz, 3KHz "output stable"
test equipment tool. 9V battery powered portable unit (circuit design added 3/05) |
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Square Wave to Sine Circuit: (Electronic Schematic / circuit added
4/02) |
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Stable 18 MHz oscillator features automatic level control clean sine wave output:
06/23/05 EDN Design Ideas / (added 10/05) Analog oscillator has stable RF
output. |
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The Wien bridge Oscillator is reborn: 06/13/02 EDN Design Ideas
/ (added 1/05) In 1940, William Hewlett and David Packard launched a
product from a garage. The product was a Wien-bridge oscillator. It consisted of a
single-pole highpass filter in series with a single-pole lowpass filter. To keep the
gain constant, the circuit used an incandescent pilot light to provide AGC (automatic
gain control).... |
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Twin-T oscillator: This circuit produces an extremely low distortion
sine wave, in spite of the non-linear devices used for amplitude limiting (D1 and D2).
The reason is first that distortion (harmonics) is fed to the minus input of the opamp
with far less loss than to the plus input, severely attenuating them. Second, this
oscillator rides a delicate balance between negative and positive feedback. This means
that only a small amount of non-linearity is needed to stabilize the amplitude. To
minimize distortion, R5 must be a high value. Although a bit more complex than the
Wien bridge oscillator, the amplitude of this oscillator is much easier to vary.
Designed by Andrew
R. Morris
(added 09/05) |
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Variable Gain Stage uses Voltage Output DAC: 10/27/94 EDN-Design Ideas
/ (added 03/05) The circuit in Fig 1 delivers a pure, buffered, and level-controlled
sine wave. With no tuning requirements, the circuit works with all crystals up to
about 30 MHz…. |
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Voltage Controls Sine Wave Frequency: 08/17/95 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) |
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Wien Bridge Oscillator: (circuit / schematic added 2/03) |
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Wien Bridge Oscillator (Rail-to-Rail) Sine Wave Generator : Circuit
Ideas for Designers - Application Notes - Advanced Linear Devices, Inc. (Circuit
/ schematic design added 6/06) |
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Wien Bridge Oscillator is Reborn: 06/13/02 EDN-Design Ideas /
(Electronic Circuit diagram added 03/03) In1940, William Hewlett and David Packard
launched a product from a garage. product was a Wien-bridge oscillator. It consisted
of a single-pole highpass filter in series with a single-pole lowpass filter. |
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Wien Bridge Oscillator keeps THD BeLow One PPM: 11/10/94 EDN-Design
Ideas / (added 01/04) The Wien-bridge sine-wave oscillator uses a light
bulb to stabilize its amplitude. The circuit doesn't have a light bulb; it sports
several enhancements that lower its distortion and generate a test signal pure enough
for testing modern op amps and high-resolution A/D converters.... |
