Transistors in saturation have a gain of about 5 to 20 only, the hfe or beta parameter does not apply at all to saturation mode (saturation is very different from using a transistor as an amplifier). You need a...
Guess you are lucky with the actual gain of those transistors then - I'd have just gone with an opamp in non-inverting mode which has very high input impedance.
Absolutely it does, but you might have to search around for code, the standard audio library supports smaller slower processors too and only has 256 and 1024 FFTs to be portable across the range of Teensy's - they don't...
But it only has about 100k input itself - the 2N3391A's gain is 250 worst case, so the 470 ohm load will be reflected back as low as 117k, in parallel with the bias circuit's 510k resistance gives about 100k. I presume...
Have you ruled out hardware issues like crosstalk, ground loops, poor layout? I'd suspect that in the first instance, especially if external cabling is long.
From the docs it looks like carrier boards put Vbat/3 onto that pin. So its expected to be used as an input (in fact it may have capacitor across it in practice so it may not be useful as an output - when in a carrier...
Crossfade between the different filters perhaps? Use a mixer object for this.
For large FIR filters FFT-based convolutions become significantly more efficient than brute-force. And for real-time response a...
You've still got to deal with signal conditioning, the Teensy can't easily drive ~100 ohm transmission lines (twisted pair, ribbon cable, etc) directly, and if the cables are not terminated with their characteristic...
Odd. Note that its normally required to have some short delay after the last clock pulse before CS goes high, according to the datasheet of the chip involved. The T4 is very fast and explicit delays normally have to be...
LVDS is pretty standard for high speed digital interfaces, for instance its typically supported by large FPGAs. At speeds upto 480Mbps like this chip uses standard 5V or 3.3V logic cannot be made to work reliably...
For 3.3V signals 74LCX is probably the family of choice, as its designed for low voltage use. 74HC is designed principally for 5V and is much slower at lower voltages. LCX is pretty fast.
But if you really want...
Yes its best practice to use external Schottky diodes to protect internal protection diodes - the internal ones are Si pn-junction so will still carry current if in parallel with an external Si pn-junction. Schottky's...
The Teensy 3 only supports 0--3.3V analog input range I believe (3.3V chip with 5V tolerant inputs doesn't mean it measures above 3.3V). Try connecting the pot ends to 0V and 3.3V
Can you show the connections to the breakout clearly - the second image doesn't have all the connections you claim to have.
Where is your call to AudioMemory? You've ignored the forum rule - its there for a very...
Like uniform partitioned convolution? For instance my attempt: https://forum.pjrc.com/threads/68939-Low-latency-two-level-partitioned-convolution-for-the-T4?highlight=fft+convolution
Others:...
Well it was a good theory (easily testable!) Sigma-delta DACs have complex reconstruction filters, don't expect the output voltage to be exactly like the digital samples (those leading and trailing edges). For that you...
I believe its on Paul's list of things to do when there aren't pandemics or chip shortages or 1000 other important things to do! It shouldn't be too hard to knock something together using the existing building blocks,...
Its always a better approach I think to leave the main clock alone and take snapshots of it if you want relative timings. That way different libraries and bits of code can share the clock without any...
They probably realized that a DAC implemented in the same CMOS process as a 600MHz logic chip and on the same die is not going to be very performant. If they had I expect it would be un-exciting in its specs.
And...
The problem is a spike of rogue values every 256 samples:
- that's just the first bit of the file. I suspect somethings overwritting the buffer somehow?
Note you need the _programmed_ bootloader chip from PJRC if you make your own version of certain Teensys. https://www.pjrc.com/store/ic_mkl02.html
There should be threads about this here.
Ah, that's useful.
Ironically though the example they use is providing a band-limited waveform to the Audio Library, but it happens I added that functionality a few years ago and without needing floating point...
The Teensy Audio library is tailored to run efficiently on particular ARM microcontrollers, using limited resources and directly interfacing DMA hardware. Faust is not that. There might well be a way to interwork...
This is phantom-powering, happens in CMOS chips due to the ESD protection diodes, and can destroy a chip if you are unlucky - never have live signals connected to a powered-down chip (unless there are series resistors...
Use an external 74LVC14 for real hysteresis?
Why aren't you debouncing in software BTW? Its cheaper, you only need a pull-up (and that could be internal even) - the only reason not to do debouncing in software is if...
q15 is too small for real-world use for FFTs. A 256 point FFT takes 8 stages, and each will lose accuracy due to rounding, so you probably only have 10 bits left, so small value coefficients may simply fall to zero. ...
Use more FFT points, and set linear frequency scale, then you might be able to see better. The frequency of the spur may be dependent on system clock frequency and differ from Teensy to Teensy perhaps. Alas Audacity...
The floating ground for the headphone output is a circuit trick to avoid needing physically large DC-blocking capacitors when the SGTL5000 chip is used in something like a mobile phone. Only use the headphone output...
Using the technical terms you'll find in DSP books, convolution (FIR filtering) is the same as cross-correlation with a time-reversed finite impulse response, so it is often implemented by cross-correlation as you only...
If you don't follow the forum rule we don't know what type directoryPath was declared as.
If it's type is char *, then be aware that == is not a string comparison operator, its a pointer comparison operator. Use...
I've often seen distortion figures for ADCs and DACs quoted at -6dB full scale - current steering DACs in particular become non-linear for larger output voltages if the outputs are clamped to virtual ground with an I-V...
Is this whine at 17.5kHz or so? If so its the same I've observed: https://forum.pjrc.com/threads/61775-A-little-FFT-demo-for-480x320-TFT-(HX8357D)?highlight=sgtl5000
Do you need to store the string? In that case you are limited by the amout of RAM available, which depends on how much you need for other purposes.
Can you stream the string directly to the TCP client and not have to...
That's -70dB down, it only takes a small issue on the analog path to add distortion at this low level - perhaps you have overloaded the Scarlett front-end? Added a ceramic capacitor into the signal path? Have a dodgy...
Hi - like to help - circuit or schematic diagram is the language we need - words are not the way to explain a circuit topology that's more than a couple of components. Draw out on paper and send a pic here, then we'll...
The MAX1681 is the chip I've used. Can be used also as a voltage doubler, 125mA max output, 90% efficiency, currently available. Much lower output resistance than the 7660.
Just wondering if you could benefit from the technique using 2 PWM outputs of low resolution and a resistive combiner circuit: http://www.openmusiclabs.com/learning/digital/pwm-dac/dual-pwm-circuits/index.html
The line outputs are line level and cannot drive any form of speaker (which requires high current). This would stress the SGTL5000 well beyond its ratings. Typically a line-level output is expected to drive impedances...
I would choose rail-to-rail opamp and use +/-5V supply personally. There are chips expressly designed for generating -5V from +5V using switched-capacitor method that mean you can just use +5V supply for everything.
705kbps is correct for 16 bit 44100SPS. 44100 * 16 = 705600
In communications its always measured in either bits per second or baud (symbols per second). So bps means bits per second.
How does it compare with the bandlimited options of waveform for quality (those aren't minimum phase, simply sinc() bandlimited)?
The table .h file has about 20000 characters in one source line, which isn't very human...
I would suggest using complex arithmetic to sum a Fourier series, then only one sin() and one cos() call are needed per sample (or perhaps less often). Rotation is simply multiplication in the complex domain.
The...
One thing I've noticed is you've conected two outputs to the same input on dac1 - this may well be the issue.
Use a Mixer4 if you want to combine signals. The rule is only one output into any input.
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