The kit is $90.00 plus shipping ($5.00). It will cost you about another $200 minimum to complete and it is intended for expert builders only. IT IS NOT SUITABLE FOR BEGINNERS, if you have to ask me dumbass questions I will charge you for time spent answering.
It produces a very nice sine wave (distortion is around -60dB ) at any frequency required, minimal step between frequencies is around 200 ppm (eg 0.01 Hz at 50 Hz), precision is 50 PPM (set by the crystal, if you buy a more expensive crystal you get better precision).
Phase amplitude and phase angle are also independently adjustable. I believe it is the only kit ever to offer all these features.
It produces a very nice sine wave (distortion is around -60dB ) at any frequency required, minimal step between frequencies is around 200 ppm (eg 0.01 Hz at 50 Hz), precision is 50 PPM (set by the crystal, if you buy a more expensive crystal you get better precision).
Phase amplitude and phase angle are also independently adjustable. I believe it is the only kit ever to offer all these features.
It's what Jim Hagerman calls a half kit, I supply the boards, a few hard to find parts, the instructions and a BOM drawn on DigiKey.
You supply the components, a case and the battery and charger (or power supply, your choice).
It's cheaper and easier this way, I don't have to spend hours counting components.
You supply the components, a case and the battery and charger (or power supply, your choice).
It's cheaper and easier this way, I don't have to spend hours counting components.
The design uses both analogue and digital techniques, I want digital precision but analogue silence.
I have a design using an AD two channel DDS chip ready to go but I have been waiting over a year for some software that I commissioned (it was meant to take 6 weeks).
If you can program a uC to talk to the DDS chip and an LCD, please PM me through this board, I am happy to pay for your services.
I have a design using an AD two channel DDS chip ready to go but I have been waiting over a year for some software that I commissioned (it was meant to take 6 weeks).
If you can program a uC to talk to the DDS chip and an LCD, please PM me through this board, I am happy to pay for your services.
Hi Mark,
I am not using one of the AD DDS chips but implemented de DDS algorithm in software using a 32 bit phase accumulator. And for the output I am using the micro controllers (Atmel MegaAVR 168) internal PWMs. For that I am using noise shaping to get 16 bits amplitude resolution. It is just in a very rudimentary state and I have not much time for it at the moment. Mid next year I hope to have a running PCB for it.
Cheers
I am not using one of the AD DDS chips but implemented de DDS algorithm in software using a 32 bit phase accumulator. And for the output I am using the micro controllers (Atmel MegaAVR 168) internal PWMs. For that I am using noise shaping to get 16 bits amplitude resolution. It is just in a very rudimentary state and I have not much time for it at the moment. Mid next year I hope to have a running PCB for it.
Cheers
Interesting.
I want to use the AD two channel DDS chip as it allows software control of phase angle as well as frequency.
The scheme mentioned above uses a very simple version of DDS implemented in CMOS - basically I have the clock running an octal counter chip which cycles continuously. There are only eight divisions in the waveform so there are only 5 required levels =+/- full scale, +/- full scale/sqrt 2 and ground. The eight divisions allows quadrature to be established on the digital side (shift two = 1/4 cycle).
I want to use the AD two channel DDS chip as it allows software control of phase angle as well as frequency.
The scheme mentioned above uses a very simple version of DDS implemented in CMOS - basically I have the clock running an octal counter chip which cycles continuously. There are only eight divisions in the waveform so there are only 5 required levels =+/- full scale, +/- full scale/sqrt 2 and ground. The eight divisions allows quadrature to be established on the digital side (shift two = 1/4 cycle).
leadbelly said:
Why not? It basically runs on low voltage like a power amp. It is a matter of choosing the right step-up transformer at the output. But up to my knowledge all synchronous DT motors intended to run from the mains (like the Philips/Premotec and Thorens ones) are basically 110V motors.
Dougie085 said:
Oops! I didn't realise I had email turned off. I'll turn it on.
leadbelly said:
Every mains voltage dual phase motor I know of uses two 110V windings. They are wired differently for 220V and 110V operation, like the difference between series and parallel crossovers.
Of course you need the correct frequency as well but that's my department.
Speed control could be done using a micro but it would involve a PID control algorithm if you want it spot on.
Its certainly not a project for an amateur unless you understand control algorithm maths well.
I have used PID algotirthms for controlling much bigger motors and it is fun. The mciro needs some sort of feedback from the turntable to know fast it is going.
Its certainly not a project for an amateur unless you understand control algorithm maths well.
I have used PID algotirthms for controlling much bigger motors and it is fun. The mciro needs some sort of feedback from the turntable to know fast it is going.
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