This is a usefull and easy to build VFO/DDS generator for Chinese AD9850/51 DDS modules
* Attention: be aware, i have tested only the AD9850 type module.
Design based on VK5TM with PIC 16F628 and LCD 2x16 characters
Software modification by G4FDN - added band frequency's.
- Frequency from 0 to theoretically 62MHz (Software go to 62MHz, usefull limit for AD9850 is +/- 40MHz)
- Step size 1Hz, 10Hz, 100Hz, 1kHz, 10kHz, 100kHz, 1MHz
- Band frequency 0Hz, 137.5kHz, 472 kHz, 1.800 kHz, 3.500 kHz, 5.258 kHz, 7.000 kHz, 10.100 kHz, 14.000 kHz, 18.068 kHz, 21.000 kHz, 24.890kHz
- Remember the last used frequency
- Rotary encoder (mechanical)
- LCD 2x16 digits in 4-bit mode
- 3 push buttons : step size, Bandfreq, spare
- PIC 16F628 programmable µ-processor
|My board without the Chinese Module||Chinese Module details|
Based original op the Pic-El Board, modifyed by VK5TM and whithout the various extra's.
Print circuits :
I made a new circuit board so i can connect the LCD module directly on the board.
A Chinese module can be placed on the board. Power consumtion is abbout 120mA,
so a power-adaptor 240V to 9V AC 1A is recommanded.
|DDS Module + CPU Board||The LCD Display, rotary en PB's|
|DDS VFO in an old RS-232 switch-box - working state||DDS VFO inside box|
* The output of the DDS Module is on the foto not connected. It goes to a BNC connector , mounted on the back of the case.
** The GREEN LED's on the LCD backlight are replaced by WHITE LED's to have lower current consumption.