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Electronics

Multiplexer S/N 4

Slight design changes to the RF Multiplexer design.

Front panel buttons B1 and B2 now extend out of the front-panel and are easily accessible. Pressing the buttons advances the state of the MUX1 and MUX2 boards.

Transmission bandwidth. This MUX has 50-Ohm impedance relays, and the 3dB bandwidth is around 1.0-1.2 GHz.
Inside of MUX-box. Two 1:8 boards with BNC connectors side-by-side. Arduino MKRZERO and Ethernet Shield on the right. A simple carrier board distributes SPI-signals from the Arduino to the MUX-boards and provides front-panel pushbuttons and LEDs. Top center is a 230VAC to 5VDC powersupply. Top left 230VAC input.

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Electronics

RF-multiplexer, 3rd prototype

This is the third prototype for the 1:8 RF-multiplexer (https://www.ohwr.org/projects/rf-mux-8ch). The board is now simplified with only one 10-pin ribbon-cable attaching it to the Arduino MKR Zero + Ethernet shield. Traco PSU for 5V supply.

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Electronics

Multiplexer, 2nd boxed version

The second multiplexer prototyped, with a slightly larger enclosure placing the Arduino Due + Ethernet Shield directly in the front panel. This requires desoldering the DC-connector on the Arduino Due.

Bandwidth, insertion loss, and pulse-shape distortion measurements should be done next.

Categories
Electronics

Mux-in-a-box

Update: Insertion-loss measurement with a spectrum analyzer:

RF-multiplexer v2 board in enclosure, controlled by Arduino Due with Ethernet Shield. SATA-cable for 4 SPI-lines (SI, SO, SCLK, CS).

When issuing commands to change state as fast as possible this combination seems to do a state-change in about 45 milliseconds - this is not verified on the RF-side (didn't measure that there is actual RF contact made/broken in those 45 ms).