| | 1 | == USB Noise Generator: !WiBo (Wireless Board) == |
| | 2 | |
| | 3 | WiBo102 is a 4.00 x 4.00” printed circuit board (PCB) designed around a Maxim, Inc. MAX2829ETN+D radio transceiver chip. This chip incorporates most of the radio functions except for the reference oscillator, baseband I/Q amps, power amps and antenna switches. |
| | 4 | |
| | 5 | Four antennas (A01-A04) are mounted directly to WiBo102 though provision is made for adding SMA connectors and using off-board antennas if necessary. Two antennas are primarily for transmission (Tx) and two for receiving (Rx). Antenna switching is possible for diversity gain. |
| | 6 | It is also possible to switch all Tx and Rx signals into a single antenna. |
| | 7 | |
| | 8 | A. PCB |
| | 9 | |
| | 10 | The PCB is a 4.00 x 4.00” FR-4 four-layer controlled impedance stackup board manufactured by [http://www.4pcb.com/index.htm Advanced Circuits, Inc.]. |
| | 11 | For orientation purposes, reference marks are shown along the top (A-D) and right sides (1-4) of the board in one inch increments. |
| | 12 | |
| | 13 | Looking from the top down with X-ray eyes, the top copper layer is the component side with all the high-frequency RF transmission lines. The dielectric under this layer is 20 mils thick. The structure of the traces is coplanar waveguide with ground (CPWG). |
| | 14 | A trace width of 30 mils and gap-to-ground of 18 mils provides a very close match to a 50ohm characteristic impedance. |
| | 15 | |
| | 16 | The next copper layer down is all ground plane. The third layer down is a signal layer with predominately vertical traces surrounded by ground plane. The fourth or bottom layer is another signal layer with predominately horizontal traces. |
| | 17 | |
| | 18 | B. Connector J3_F and I/O |
| | 19 | |
| | 20 | This is a 40-pin 2mm dual-inline connector which mates BiBo’s control signals, +3.3 VDC power and ground to WiBo102. |
| | 21 | |
| | 22 | BiBo’s ADC (analog-to-digital conversion) and DAC (digital-to-analog) conversion comes from an Analog Devices AD9860 MxFE processor on the [wiki:Internal/ISBNoise/BaBo BaBo] board. Digital RADIO_IO_x signals come from a Xilinx Spartan 3 on [wiki:Internal/ISBNoise/BaBo BaBo]. |
| | 23 | |
| | 24 | RADIO_IO_1/3/4 download programming coefficients to the MAX2829. |
| | 25 | |
| | 26 | RADIO_IO_3/4 are shared with U2 ([wiki:MM74HC595.pdf 74HC595]), an 8bit serial in parallel out shift register. |
| | 27 | U2 in turn controls five functions, namely, turn on/off of the 2GHz and 5GHz power amps, MAX2829 RXENA and TXENA signals and the MAX2829 shutdown (/SHDN). |
| | 28 | |
| | 29 | Assuming the MAX2829 has already been programmed, to enable a TX RF output the user must program a 11001xxx into U2. |
| | 30 | |
| | 31 | NOTE! Do not turn on both the 2GHz and the 5GHz power amps at the same time! ALSO! Do not turn on both the RXENA and TXENA lines (not sure why?). |
