wow, thanx for reply, its very helpfull for me and give me some
consideration about my project.
I'm sorry about my english before, its not grammatical and very bad i
think.
OK this my real problem.
I need to make 9 phase sinusoidal wave generator. This wave generator
can also be operated on 5 phase. Frequency for this system is on the
range about 0 Hz till 150 Hz.
I have two plans to solve this problem
First i'll use VCO to generate clock for one counter which serve
address data for 9 eeprom. So each eeprom will contain data for each
phase of sinus. Data from eeprom is then converted to analog with dac.
The problem in this system is i can't switch my 9 phase system to 5
phase system, because the data in eeprom is fixed.
Second, i'll use microcontroller as clock generator for counters, there
are nine counters to serve nine address eeprom. So each eeprom will
contain similar data that is one sinusoidal data.The phase control is
arranged by microcontroller.
The reason why i use 16-bit system is for precision. Any comment for
that?
---
If I were doing this project, the first thing I'd do would be to
determine what the interval between samples would be and what the
amplitude resolution would need to be.
Assuming that a 1° step would be adequate for the purpose means that
I'd need 360 EPROM addresses to step through, and if an amplitude
resolution of 1 part in 255 would be enough, an 8 bit DAC would
work.
Now, having 9 phases being output simultaneously, in real time,
means that I'll need 9 DACs and some way to hold onto the data as
it's coming out of the EPROM and time it appropriately. This will
work:
+-------------------+
HFCK>--|> COUNT |
| Q Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+-+
| | | | | | | | |
| | | | | | | | |
+-+-+-+-+-+-+-+-+-+-+
| A A A A A A A A A |
| LUT |
| D D D D D D D D |
+--+-+-+-+-+-+-+-+--+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT9
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT8
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT7
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT6
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT5
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT4
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT3
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH9>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT2
| +-|-|-|-|-|-|----------|D |
| | +-|-|-|-|-|----------|D |
| | | +-|-|-|-|----------|D |
| | | | +-|-|-|----------|D |
| | | | | +-|-|----------|D |
| | | | | | +-|----------|D |
| | | | | | | +----------|D |
| | | | | | | | PH1---|> |
| | | | | | | | +------+
| | | | | | | |
| | | | | | | |
+-+-+-+-+-+-+-+-+-+
| D D D D D D D D |
PH1>----|> LATCH |
| Q Q Q Q Q Q Q Q |
+-+-+-+-+-+-+-+-+-+
| | | | | | | | +------+
+-|-|-|-|-|-|-|----------|D OUT|-->OUT1
+-|-|-|-|-|-|----------|D |
+-|-|-|-|-|----------|D |
+-|-|-|-|----------|D |
+-|-|-|----------|D |
+-|-|----------|D |
+-|----------|D |
+----------|D |
PH1---|> |
+------+
The counter shown has a syncronous preset and presets to 360 when it
reaches 0 + 1 phase 9 clock, and the clocks would look like this:
_
PH1__| |_____________________________________________
_
PH2____| |____________________________________________
_
PH3______| |__________________________________________
_
PH4________| |________________________________________
_
PH5__________| |______________________________________
_
PH6____________| |____________________________________
_
PH7______________| |__________________________________
_
PH8________________| |________________________________
_
PH9__________________| |______________________________
_
PH1____________________| |____________________________
OK, what about the counter clock?
For a 150Hz sinewave out of the DACs it would have to be going 360
times faster than 150 Hz, or 54kHz. Easy.
54kHz is about about 18.52µs
The phase clocks would have a period of 1/150Hz, or about 6.67ms,
but since there would be nine of them per cycle their adjacent
leading-edge-to-leading-edge spacing would have to be 1/9th of that,
or about 741µs. Duck soup, and easy to do by counting down HFCK
appropriately and running that signal through a 9 bit Johnson
counter.
Seems like it would be easy to modify the system to work as a 5
phase generator, but my brain hurts.