Syntezer DDS V3.4

A simple inexpensive multi-band synthesizer DDS with 2x16 LCD display and a large amount of possibilities-function.


Basic parameters:

The range work 0-40Mhz
The signal level 1Vpp 200ohm
LCD 16x2
Power supply 8-12V 0.12

Features and Capabilities:

Encoder to change the frequency, and the button on it to change the step of tuning. Available steps are Fast, Mid, Slow
Keys band up and down from 160m to 2m (unnecessary bandwidth, you can turn off the menu)
CW modulation, LSB, USB
Rit and Xit + -50.00khz (accuracy at 10Hz)
LOCK button lock knobs
PTT input
ABCD output to the decoder bands
AB output to the modulation decoder



Using encoder you can change the frequency. Using swith on it you can change the  frequency step F, M, S.
UP and Down keys change the band. The current frequency operation is stored when changing bands on another.
Press the button MOD to change the modulation CW, LSB, USB. This changes the output frequency with the value set in the menu.
XIT key activates and deactivates the drift of the transmitter and the RIT key receiver drift.
LOCK key locks the knob.
Tunable range is limited to the bandwidth.
The buttons work by shorting the input to ground.
Connect the encoder input ENC1 and ENC2 and mass.
ABCD output Connecting to a decoder bands on-chip CD4028

160m 0 0 0 0
80m 1 0 0 0
40m 0 1 0 0
30m 1 1 0 0
20m 0 0 1 0
17m 1 0 1 0
15m 0 1 1 0
12m 1 1 1 0
10m 0 0 0 1
6m 1 0 0 1
4m 0 1 0 1
2m 1 1 0 1

Additional outputs A B bottom plates are for connecting modulation decoder-chip CD4028

CW 0 0
LSB 1 0
USB 0 1
AM,FM 1 1

Examples of connecting the switch bands and modulation performed by a SP7EWL


To enter the settings of the synthesizer must hold the button encoder and turn the power on. For each band you can set whether to be available or not., or use external Multiplier , or intermediaty frequency to be subtracted, added, or is it not to be.
The values are change by turning the encoder and click the button.

By clicking the button band down, go to the following menu items:
1. Setting Fosc local 125MHz
2. Setting Fpoś
3. Set the correction CW
4. Set the correct LSB
5. Set the correct USB
6. Setting the step for retuning Fast
7. Setting the step for retuning Mid
8. Setting the step for retuning Slow
9. Enable transmit on CW without an intermediate



To restore the synthesizer to the factory settings, press both UP and DOWN keys and turn on the power on.





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