RFzero Signal Generator

Here my solution to the RFzero Signal Generator:

I decided for the graphical TFT display, two encoders (for frequency and attenuation) and a keypad.

I used a housing I had in stock, it is a little small so I had to shrink everything.
So I had to remove all SMA connectors and connect by soldering shielded wire directly to the PCBs.

The components in my generator are:
Display: 2.8″ TFT SPI 240×320 (eBay)
Supply: 8-20V DC (13V 0.06A) with step down converter to 5V (eBay)
Encoder: top is for frequency, bottom is for attenuation
Expander: SX1509 (eBay)
Attenuator: RFzero I2C in mode 7  (11 bits, 0-106,5 dB in 0,5 dB steps). Please note, this is a RFzero prototype and will not be available for sale because of bad performance at high attenuation. We have a 76 dB version in progress, maybe that will be available at a later time.

Front view (no GPS antenna)
Top view with short form command overview
Top view
View on back side of front panel
Display and LEDs, with GPS antenna connected

LEDs:
Green – Power ON
Red –     Output on
Blue –    GPS impulse
Yellow –  GPS Ready

Here the schematic in pdf of the external connections to the display, attenuator, SX1509, encoders, keys  and keypad:  SigGen_oz2xh_200924

 

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