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127 lines
5.0 KiB
Markdown
127 lines
5.0 KiB
Markdown
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[](https://github.com/marketplace/actions/arduino_ci)
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[](https://github.com/RobTillaart/WaveMix/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/WaveMix/actions/workflows/jsoncheck.yml)
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[](https://github.com/RobTillaart/WaveMix/blob/master/LICENSE)
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[](https://github.com/RobTillaart/WaveMix/releases)
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# WaveMix
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WaveMix is an Arduino library to mix two signals (A and B) with an adaptive weight.
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## Description
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WaveMix is a very simple library to mix two signals (A and B) with an adaptive weight.
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Depending on the weights applied the output signal (O) looks more on signal A or on signal B.
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A gain can be applied to amplify weak signals or to be used for modulation.
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Inspired by - https://www.codeproject.com/Articles/5323200/On-how-to-mix-two-signals-by-using-Spectral-Foreca
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Differences
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- simpler algorithm
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- WaveMix works on streams of measurements too.
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## Interface
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The main functions of the WaveMix:
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- **explicit WaveMix()** Constructor
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- **void setWeight(float weight1, float weight2)** set the weight of the channels A and B.
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The weights do not need to be normalized, so one can use e.g **setWeight(7, 13)** See below.
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- **float getW1()** return the normalized weight for channel A.
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- **float getW2()** return the normalized weight for channel B.
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- **void setPercentage(float percentage)** sets the weight for channel A preferably to 0 <= percentage <= 100.
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Channel B will have 100 - percentage.
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- **void setGain(float gain)** sets the gain factor.
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An important use of gain is to amplify weak signals but one can also use it as a modulator of a signal.
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See examples.
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- **float getGain()** return the gain set.
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- **void setOffset(float offset)** sets the offset for the output signal.
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Typical used to align the zero level.
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- **float getOffset()** return the current offset used.
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- **float mix(float s1, float s2 = 0)** returns the weighted average of signal1 and signal2.
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Signal2 is made optional to allow single signal processes e.g. modulation by **setGain()**.
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## Operation
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See examples.
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#### Weights
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**setWeight()** typically uses positive weights, e.g. **setWeight(7, 13)**
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counts A for 7/20 part and B for 13/20 part.
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It is also possible to use one or two negative weights.
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Using negative weights means effectively the input value is inverted before it is added.
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E.g. **setWeight(-1, 0)** would effectively invert signal A.
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Only restriction to the weights is that the sum of the weights may not be zero.
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#### Amplification
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Weights cannot be used to amplify the signal in absolute sense, use **setGain()** for that.
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By constantly updating the gain (0..max) one can implement **Amplitude Modulation**.
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When the gain is negative, the output is effectively inverted.
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## Future ideas
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#### N channel variant.
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- add **setValue(uint8_t channel, float value)** allow update of channels at a different frequency.
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- add **getValue()**, read the current output given the value of the channels. OR
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- add **getValue(uint8_t mask = 0xFF)**, read the current output given the value of selected channels.
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- add **setMask(uint8_t mask = 0xFF)**, select channels. ease of use? **getValue(mask)** still needed?
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- add **getMask()**, read back \_mask;
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- note that **mix()** can be implemented with the above functions.
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- add **setWeight(uint8_t channel, float weight)** need internal array of weights and \_sum
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- add **float getWeight(uint8_t channel)** Normalized or not?
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Not normalized allows easier increment per channel. Needs a **float getTotalWeight()**.
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- add constructor **WaveMix(uint8_t channels = 8)** with parameter to set the number of channels? \[NO\]
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- or do we need **WaveMix2()**, **WaveMix4()**, **WaveMix8()**, or even **WaveMix16()**, **WaveMix24()**, **WaveMix32()** class?
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**WaveMix4()** and **WaveMix8()** seems to be realistic in terms of performance.
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**WaveMix8()** can be used for 2-8 channels, using a uint8_t mask.
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More channels will be much slower, so upon request the 16 and 32 variant? other variants can be obtained by masking.
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#### Medium
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- performance test.
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#### Low
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- think of integer version
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- performance
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- integer weights
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- math in **int32_t** with last moment float conversion
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- Templated version
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- float vs double vs int
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- maybe upon request.
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- dynamic weights
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- add **increment(float)**
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- add **decrement(float)**
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- percentages? hard for multichannel?
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- default parameters
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- gain = 1.0
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- percentage 50%
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- offset = 0.0
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- **reset()** needed?
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#### wont
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- add top clipping
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- add **setMaximum(float)**
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- add **setMinimum(float)**
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- needs an enable/disable per limit.
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becomes more complex than let the user constrain the output. |