Release status: experimental [box doku]

Description use the VGA port to transmit I/Q signals on any frequency
Author(s)  siro (siro)
Last Version  0.1 ()
License  GPL

Software Defined Radio Transmitter[Bearbeiten | Quelltext bearbeiten]

Description[Bearbeiten | Quelltext bearbeiten]

Hardware to transmit anything on any frequency. That means any information / modulation can be transmited on a channel between 100 and 2400 Mhz, which is the possible internal PLL frequency-range for ADRF6755. The I/Q signals are feed through a VGA-compatible 15pole-DSUB connector.
This board is intended to be used with VGAtoBaseband.
While SDRT was configured using a teensy this board is connected to the VGA i2c and can be controlled from any Software that has access to this bus. The board has a 50Ohms SMA connector transmitting about todo using VGA signals (0.8Vpp).


Board[Bearbeiten | Quelltext bearbeiten]

Overview[Bearbeiten | Quelltext bearbeiten]

  • VGA DSUB connector, baseband input
  • power jack DC 6 - 7 V > 600mA
  • 3 LEDS
    • power
    • opamp power
    • PLL locked
  • SMA connector, rf output
  • switch (rf disable/enable)

Clock[Bearbeiten | Quelltext bearbeiten]

26 Mhz TCXO +-2 ppm 1.8V
As there is a frequency error of at least +-2ppm the software has to add a compensation offset to the selected rf frequency. The adrf6755 can be configured in 1Hz steps. The offset has to be measured initially using precise frequency counters.

Low pass[Bearbeiten | Quelltext bearbeiten]

The low pass is critical as it phase-shifts the high frequencies.
Phase shifts can be ignored in analog audio applications, but not in digital transmissions. It might be necessary that the software compensates this phase-shift.
The channels are terminated using 110 and 120 Ohms to have a voltage level of about 0.8Vpp.

Differential Opamps[Bearbeiten | Quelltext bearbeiten]

Opamps are used to generate two differential signal with a common mode voltage of 0.5V. Each signal is filtered and then feed into the Adrf6755.

SPI/I2c[Bearbeiten | Quelltext bearbeiten]

The ADRF6755 can be configured by I2c or by SPI. External pins are connected to this port. Upon startup the ADRF6755 is in I2c mode. Once in SPI mode the board has to be powered to use I2c again. Place resistors (R49, R31, R50, R51) accordingly to use VGA port or external port. The SPI interface should have series resistance of more than 50 Ohms.

ADRF6755[Bearbeiten | Quelltext bearbeiten]

  • reference design
  • internal vco and pll is used
  • LO path is disabled
  • input multiplier 1:1
  • internal LO divider 1:4
  • fin: 26Mhz ac coupled
  • internal gain control
  • lo output freq:
fout = fin / 4 * ( INT + (mod / frac) )
INT, MOD, FRAC are register values

HF Power amplifier[Bearbeiten | Quelltext bearbeiten]

The ADL5601 amplifies the HF signals by about +15 dB.

  • 83 mA @ 5V

Layout[Bearbeiten | Quelltext bearbeiten]


Partlist[Bearbeiten | Quelltext bearbeiten]

Part Manufacturer part ID Size
C1 ESD31C103K4T2A-18 C0402
C2 04023A101FAT2A C0603
C3 GRM1885C1H102FA01D C0603
C4 04023A101FAT2A C0402
C5 C0603C104J4RACTU C0603
C6 04025U100CAT2A C0402
C7 C0603C104J4RACTU C0603
C8 04025U100CAT2A C0402
C9 04025U100CAT2A C0402
C10 04025U100CAT2A C0402
C11 C2012X5R1H105K085AB C0805
C12 VJ1206V475MXJTW1BC C1206
C13 C2012X5R1H105K085AB C0805
C14 C0603C104J4RACTU C0603
C15 C0603C104J4RACTU C0603
C16 C0603C104J4RACTU C0603
C17 04025U100CAT2A C0402
C18 C0603C104J4RACTU C0603
C19 04025U100CAT2A C0402
C20 06031U560GAT2A C0402
C21 04025U100CAT2A C0402
C22 C0603C104J4RACTU C0805
C23 ESD31C103K4T2A-18 C0603
C24 VJ1206V225MXXTW1BC C1206
C25 C1206C106K3PACTU C1206
C26 C0603C104J4RACTU C0603
C27 VJ0603A101JXACW1BC C0603
C28 04025U100CAT2A C0402
C29 GRM1885C1H102FA01D C0402
C30 GRM1885C1H102FA01D C0603
C31 C0603C104J4RACTU C0603
C32 C0603C104J4RACTU C0603
C33 C0603C104J4RACTU C0603
C34 04025U100CAT2A C0402
C35 C1206C106K3PACTU C1206
C36 04023A101FAT2A C0402
C37 04023A101FAT2A C0402
C39 C0603C104J4RACTU C0603
C40 C0603C104J4RACTU C0603
C41 C0603C222K5RAC7411 C0603
C42 C0603C104J4RACTU C0603
C43 04023A101FAT2A C0603
C44 04023A101FAT2A C0603
C45 04025U100CAT2A C0402
C46 C0603C104J4RACTU C0603
C47 C0603C104J4RACTU C0603
C48 04025U100CAT2A C0402
C49 VF 220/10 P-D8 PANASONIC_E
C50 C0603C104J4RACTU C0603
C51 C0603C104J4RACTU C0603
C52 MKS2B051001N00MSSD C050-024X044
C56 C0603C104J4RACTU C0603
C57 04023A101FAT2A C0603
C58 GRM1885C1H102FA01D C0402
C59 ESD31C103K4T2A-18 C0603
C60 C2012X5R1H105K085AB C0805
C61 04025C122JAT2A C0603
C62 06031U680FAT2A C0603
C63 GRM1885C1H102FA01D C0603
C64 C0603C104J4RACTU C0603
C65 C0603C104J4RACTU C0603
C67 06031U560GAT2A C0402
C70 04025C122JAT2A C0402
C71 C1005X8R1C473K/EPOXY C0402
C72 VJ0402Y561KXACW1BC C0402
C73 VJ0402Y561KXACW1BC C0402
D2 TZM5232B-GS18 SOD80C
IC1 24LC21SN SO-08
IC2 7805DT TO252
IC3 7805DT TO252
IC4 TS520533 SOT25
J2 RAPC722BK SPC4078
L1 BLM18PG 331 603
L2 BLM18PG 331 1812
L3 BLM18PG 331 603
L4 0603HL-471XJRB 603
L5 ILSB0805ERR68K L2012C
L6 ILSB0805ERR68K L2012C
L7 ILSB0805ERR68K L2012C
L8 ILSB0805ERR68K L2012C
L11 LQM31PN4R7M00L 1206
L12 LQM31PN4R7M00L 1206
LED1 LED 3mm green LED3MM
LED2 LED 3mm green LED3MM
LED3 LED 3mm green LED3MM
R1 ERA-3AHD100V R0603
R2 ERA-3AED470V R0603
R3 ERA-3AED470V R0603
R4 RT0603FRE0747KL R0603
R5 RT0603FRE0747KL R0603
R6 RT0603FRE0747KL R0603
R7 ERA-3AED221V R0603
R8 S07K40 S07K40
R9 ERA-3AED121V R0603
R10 ERA-3AED101V R0603
R11 ERA-3AED471V R0603
R12 ERA-3AED472V R0603
R13 ERA-3AED471V R0603
R14 ERA-3AED121V R0603
R15 ERA-3AED103V R0603
R16 ERA-3AED123V R0603
R17 ERA-3AED49R9V R0603
R18 ERA-3AED121V R0603
R19 PCF0603R-35K7BT1 R0603
R20 RR0816P-8062-D-88C R0603
R21 ERA-3AED103V R0603
R22 ERA-3AED102V R0603
R23 ERA-3AED49R9V R0603
R24 ERA-3AED49R9V R0603
R25 ERA-3AED472V R0603
R26 ERA-3AED221V R0805
R27 ERA-3AED471V R0603
R30 ERA-3AED471V R0603
R31 ERA-3AED472V R0603
R32 ERA-3AED49R9V R0603
R33 ERA-3AED151V R0603
R34 ERA-3AED161V R0603
R37 ERA-3AED472V R0603
R41 ERA-3AED471V R0603
R42 ERA-3AED471V R0603
R43 ERA-3AED471V R0603
R44 ERA-3AED471V R0603
R45 ERA-3AED161V R0603
R46 ERA-3AED472V R0603
R47 ERA-3AED111V R0603
R48 ERA-3AED111V R0603
R49 ERA-3AED472V R0603
R50 ERA-3AED472V R0603
R51 ERA-3AED472V R0603
S1 SS12SDH2 EG1218
SV1 pin header 1x6 MA06-1
U$1 7Q-26.000MBG-T MT
U$2 ADRF6755 LFCSP56
U$4 LT3580 MSOP8_EXP
U1 AD8132ARMZ SOP65P490X110-8N
U2 AD8132ARMZ SOP65P490X110-8N
X1 571-1734344-1 HDR15RA
X2 SMA-142-0711-871/876 J502-ND-142-0711-871/876

TODOs[Bearbeiten | Quelltext bearbeiten]

Summary[Bearbeiten | Quelltext bearbeiten]

Links[Bearbeiten | Quelltext bearbeiten]