Very low noise VCO-PLL for Digilite 23 cm

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Joined: Mon Apr 09, 2012 12:03 am

Very low noise VCO-PLL for Digilite 23 cm

Post by OA5ATV » Sat Sep 27, 2014 2:59 am

Hello friends;
Digilite is a great project. I have worked with low noise OL and share with you;
I successfully use the PLL module SM6VFS, as a local oscillator for Digilite 23 cm, when I buy this module was half full, lacked the microcontroller and the reference oscillator.
Now I use a TCXO 13 MHz Toyocom and PIC12F629 controlling the ADF4106 PLL, It is a minimalist design.
I make the circuit schematic and hex code, to adjust the frequency serves a Sony TV remote control, with the "Ok" key you enter the adjustment mode, with the same key you can also exit the setting mode, you must press a total of 4 digits, the first two set the value of N and the last two the value of A, for example:
This results:
N = 12 and A = 2

values of N and A are recorded in the EEPROM of the pic.
between digit and digit pressed the red LED flashes to indicate the adjustment, you have a one-minute window to adjust once you turn on pll, after which time the pic sleep.
Values for ADF4106 PLL Analog Devices,PS=1/8,TCXO Toyocom 13,000MHz,R=1,Fref=13MHz

Fout = Fref/R*[(PS*N)+A]
Fout = 13*[(8*12)+2]
Fout = 1274 MHz

For PIC12F629 pins are:
CLOCK GPIO.0 (pin 7)
DATA GPIO.1 (pin 6)
ENABLE GPIO.2 (pin 5)
IR_SENSOR GPIO.3 (pin 4)
LOCKED INPUT GPIO.4 (pin 3), "1" = Locked and "0" = Unlocked
LED_ROJO GPIO.5 (pin 2)

The IR sensor is TFMS 5400 Receiver for infrared remote control systems.
zip file contains the schematic,pics, a view spectrum SDR and hex for pic12F629.

73' all
PD:I'm sorry, I'm using google translator :D
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