TX8M `Satrian`daughterboard for SDR MK1.5 `Andrus`

Its a bird .. no, its a plane ..no .. may be its a spaceship?!
- The TX8M 'Satrian' -

All the Analog Devices development boards you always wanted to have, but found ridiculously expensive to purchase integrated to a single system. It is a "Swiss army knife" of the radio, designed to be a sort of a "lego", so many features do not depend on each-other and can be left uninstalled to reduce cost, if particular functionality is not needed.


The non-definitive list of building blocks:
  • AD9957 based 0..450MHz exciter with CW and direct 14-bit IQ modulation modes (max bandwicth is yet to be determined, but at least 200kHz is realistic)
  • ADF4351 based DSS signal synthesizer, 30MHz to 4GHz
  • ADL5801 up/downconverter, 1MHz .. 4GHz (runs off the ADF4351)
  • ADL5330 quadrature downconverting mixer, 4MHz .. 2GHz
  • ADS1675 24-bit I/Q sidechain (with MK1.5 it will give about 200kHz bandwith)
  • AD8302+ADL5513 based Vector Network analyzer, working LF to 2.7GHz as 60dB vector analyzer (with phase and reflection) and LF to 4GHz as just 90dB scalar network analyzer.
  • ADRF6510 1 to 30MHz filters in a configuration what allows notch and bandpass filtering in 1MHz steps
Not counting preamps, VGA-s, RF switches, on-board ADC-s and DAC-s etc.

By adding the TX8M daughtercard, the SDR MK1.5 radio is now capable of
  • receiving up to 2GHz.
  • able to transmit up to 450MHz without external filtering and up to 4.5GHz with external filters in front of power amplifier
  • some outboard filters can get receiver working up to 6.4GHz.
  • with built-in dedicated LNA preamp, the inexpensive bandpass filter can be added and the radio becomes a really good tool for receiving 400MHz satellites and 1.4GHz cosmic radio waves monitoring device.
  • allows measuring the cable losses, plot filter characteristics, check antenna and feeder matching etc.
  • a RF signal generator from kHz range to 450MHz
  • a moderate RF signal generator from 30MHz to 4GHz
The I/Q mixer output is also routed to the pair of 24-bit ADC converters running in a 1+MSPS region. The MK1.5 SPI bus is relatively slow and allows 24-bit transfers of the IQ data to only about 200kHz bandwidth worth, but the real usable noise- and spikes-free dynamic range on that case will be around 105dB without any oversampling or compromise, while the total dynamic range is around 115dB.


The daughtercard has a native Raspberry Pi gpio/spi/i2c connection! If there will be ever any software to support it, the same 24-bit ADC converters will deliver about 1MHz wide piece of spectrum in 24-bit depth through Raspberry!