Changes between Version 3 and Version 4 of Internal/NoiseGenerator/Hardware/WiBo


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Timestamp:
Jan 14, 2007, 1:02:59 AM (18 years ago)
Author:
anonymous
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  • Internal/NoiseGenerator/Hardware/WiBo

    v3 v4  
    1 == Orbit Noise Generator Wireless Board (!WiBo) ==
     1= Orbit Noise Generator Wireless Board (!WiBo) =
    22
    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.
     3WiBo102 is a 4.00 x 4.00” printed circuit board (PCB) designed around a Maxim, Inc. MAX2829ETN+D radio transceiver chip.
    44
    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.
     5=== MAX2829ETN+D Transciever WLAN chip (U1) ===
    76
     7The MAX2829 is a complex multifunction radio transceiver chip that incorporates most of the radio functions except for the reference oscillator, baseband I/Q amps, power amps and antenna switches. Please refer to the data sheet and eval board notes for more information than can be given here (also check http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4532). Chip configuration is done by !BiBo over the serial bus through the programming pins:
    88
    9 A.      PCB
     9||!BiBo function||WiBo102 function||MAX2829 function||
     10||RADIO_IO_1||*CS||Chip Select, active low||
     11||RADIO_IO_3||SCLK||Serial ClocK||
     12||RADIO_IO_4||DIN||Data IN||
     13                       
     14On power up and without programming the MAX2829 is in a low power “all off” state.  The internal LO will lock to 2437 MHz but all input and output signals will be disabled.  Current draw will be around 200-240 mA.
     15
     16=== RF Control Register (U2) ===
     17                       
     18U2 (74HC595), an 8bit serial in parallel out shift register (http://www.fairchildsemi.com/ds/MM/MM74HC595.pdf). Register programming  programming is done with:
     19
     20||!BiBo function||WiBo102 function||74HC595 function||
     21||RADIO_IO 2||U2 RCK||Register U2 output||
     22||RADIO_IO 3||U2 SCK||Serial Clock||
     23||RADIO_IO 4||U2 SER||Serial Data In||
     24
     25 This register controls five functions, namely, turn on/off of the 2GHz and 5GHz power amps, MAX2829 transmit and receive control signals and the MAX2829 shutdown. The register bit assignment is given in the following table:
     26
     27||01234567||Function|| 
     28||1xxxxxxx||turn MAX2829 on (/SHDN)||
     29||x1xxxxxx||turn MAX2829 TX on (TXENA)||
     30||xx1xxxxx||turn MAX2829 RX on (RXENA)||
     31||xxx1xxxx||5G PA: 5GHZ power amp on||
     32||xxxx1xxx||2G PA: 2GHz power amp on||
     33||xxxxx1xx||SPARE 1 output on||
     34||xxxxxx1x||SPARE 2 output on||
     35||xxxxxxx1||SPARE 3 output on||
     36||xxxxxxxx1||SPARE 4 output on (9th bit)||
     37
     38U2 shares serial clock and data lines (RADIO_IO 3 and RADIO_IO 4) with MAX2829.
     39 
     40Note: 0 is the first bit in, so shift in reverse order         
     41       
     42=== LTC 1994 Baseband amps (U3xx, U4xx) ===
     43
     44U300, U320 are high speed differential opamps (LTC1994) wired in a 2nd order Butterworth filter with cutoff of 10MHz.  They act as reconstruction filters for the output of the AD9862 DACs, which are current mode differential outputs of 0-20mA.  These amps also DC offset their output to 1.1 VDC to optimally match the MAX2829 inputs.
     45These amps are enabled only when TXENA is high, thereby saving about 18mA of power.
     46
     47U400, U420 are buffer amps (gain=1) for the MAX2829 baseband I/Q signal outputs (which have 60k ohm output impedance).  These amps provide simple 1st order RC filtering with cutoff F = 6 MHz.  U400,U420 DC offset to 2.0VDC before sending the baseband I/Q signals to BiBo’s AD9860.  These amps are enabled only when RXENA is high.
     48
     49=== uPG2035 Switches (U3, U4, U5) ===
     50
     51U3,U4 and U5 make up a switching matrix which offers several antenna diversity options.
     52These are fast switching low-loss DPDT switches.
     53
     54U5 is the TX output switch which switches 2.4 and 5.6 GHz MAX2829 outputs between two antennas A03 and A04.  When LED3 is lit (power up default), the switch is “crossed” so the MAX2829 2.4 GHz output is routed to antenna A03 and 5.6 GHz is routed to A04.
     55
     56U4 is the RX input switch which switches antennas A01 and A02 to both the 2.4 and 5.6 GHz MAX2829 inputs. When LED1 is lit (power up default), the switch is “crossed” so MAX2829 2.4 GHz input is routed to antenna A02 and 5.6 GHz is routed to A01.
     57
     58The default design does not incorporate U3.  Some soldering and jumpering is required to bring U3 into the mix which enables single antenna operation or maximum spatial antenna seperation (using A01 and A04).  No further notes are given here.
     59 
     60=== AWL6951 Power amp (U6) ===
     61
     62The AWL6951 is a dual mode (2.4 and 5.6GHz RF power amp) with enable signals and log detectors for measuring power output.  U2 control signals 2G PA and 5G PA should only be enabled one-at-a-time to prevent overheating the chip.  AUX_ADC_B1 and AUX_ADC_B2 measure the log detector outputs of the 2G and 5G amps respectively.  The following measurements were taken,
     63
     64 * Pout (2.4GHz) @ 210 mA = 20.5 dBm (right on spec) Vout(logDET) = 0.727 V
     65
     66 * Pout(5.3GHz) @ 220 mA = 19.0 dBm (right on spec) Vout(logDET) = oops ?
     67
     68 * Pout(5.9GHz) @ 220 mA = 15.0 dBm (-3 dB off spec) Vout(logDET) = oops ?
     69
     70Current draw is that of just the power amp and RF power measured at output of SMA connector when 100kHz modulation is transmitted.  Otherwise MAX2829 and other circuitry draws about 170mA so total is about 480-500 mA.
     71       
     72NOTE! It is VERY easy to over drive the power amp at either 2.4 or 5.6 GHz.  This causes an UNUSUALLY high current draw by the power amp, WATCH IT !
     73
     74=== Reference Oscillator (U9) ===
     75
     76U9 is a 40 MHz VCXO reference oscillator.
     77Measured frequency standard deviation over a 10 second period is about 10 Hz.
     78   
     79AUX_DAC_B controls the frequency offset pin.  This can adjust any gross frequency offsets that may exist between different WiBos.  Resistors R221 and R222 act as a 10:1 divider of AUX_DAC_B so the total frequency deviation may be adjusted up or down by changing R221/2.
     80
     81The default measured frequency range is approx. 550Hz/volt at 40 MHz. 
     82At 2.4GHz the frequency control will be approx. +-42kHz or 330 Hz/step of AUX_DAC_B.
     83At 5.6GHz the frequency control will be approx. +-100kHz or 780 Hz/step.
     84
     85=== Antennasa (A01-A04) ===
     86Four 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. It is also possible to switch all Tx and Rx signals into a single antenna.
     87
     88== PCB ==
     89
    1090The PCB is a 4.00 x 4.00” FR-4 four-layer controlled impedance stackup board manufactured by Advanced Circuits, Inc.(http://www.4pcb.com/index.htm). 
    1191For orientation purposes, reference marks are shown along the top (A-D) and right sides (1-4) of the board in one inch increments.
     
    20100RADIO_IO_1/3/4 download programming coefficients to the MAX2829.
    21101
    22 RADIO_IO_3/4 are shared with U2 (74HC595), an 8bit serial in parallel out shift register.  http://www.fairchildsemi.com/ds/MM/MM74HC595.pdf
    23 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). Meaning of control signals
    24 
    25102Assuming the MAX2829 has already been programmed, to enable a TX RF output the user must program a 11001xxx into U2. 
    26103
    27104NOTE! 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?).
    28 
    29 == Connector J3_F and I/O ==
     105       
     106=== Connector J3_F and I/O ===
    30107 
    31108This is a 40-pin 2mm dual-inline connector which mates BiBo’s control signals, +3.3 VDC power and ground to WiBo102.
     
    53130||U3 switch(straight=0,cross=1)||RADIO_IO 5||40||39||RADIO_IO 6||U4 switch(straight=0,cross=1)||
    54131
    55 === Control Register U2 ===
    56                        
    57 Note: A is the first bit in, so shift in reverse order         
    58                
    59 ||012345678||Function||
    60 ||1xxxxxxxx||turn MAX2829 on (/SHDN)||
    61 ||x1xxxxxxx||turn MAX2829 TX on (TXENA)||
    62 ||xx1xxxxxx||turn MAX2829 RX on (RXENA)||
    63 ||xxx1xxxxx||5G PA: 5GHZ power amp on||
    64 ||xxxx1xxxx||2G PA: 2GHz power amp on||
    65 ||xxxxx1xxx||SPARE 1 output on||
    66 ||xxxxxx1xx||SPARE 2 output on||
    67 ||xxxxxxx1x||SPARE 3 output on||
    68 ||xxxxxxxx1||SPARE 4 output on, 9th bit||
    69132
    70