Digital Transciever [CNW:Counter]

Digital transciever architecture:

Receiver part (Analog-to-Digital Converter and Digital Down Converter), Clock generation unit, Digital Signal Processor unit and Transmitter part (Direct Digital Synthesis).
Receiver and transmitter part in detail.
TRX architecture

Basic transmitter parameters:

Full-scale output level: 0.35 V p-p into 50 Ohm (-5 dBm)
Output frequency: up to 120 MHz
Wideband SFDR: 65 dB (61.5 MHz, 17-bit word)
Narrowband SFDR (5 kHz): 86 dB (61.5 MHz, 17-bit tuning word)

FSK/BPSK pattern modulation: max. 10 MSa/s
AM pattern modulation rate (I,Q): max. 2.5 MSa/s

Basic receiver parameters:

Full-scale input level: 1.2 V p-p into 50 Ohm (+5.5 dBm)
-3 dB signal bandwidth: 0.11 MHz to 130 MHz
Dynamic range: 145 dBFS/sqrt(Hz) (40 MHz VCXO clock)
Dynamic range: 148 dBFS/sqrt(Hz) (65 MHz XO clock)
Total jitter (RMS): 1.2 ps (40 MHz VCXO clock)
Total jitter (RMS): 0.40 ps (65 MHz XO clock)
Harmonic distortion, 2nd, 3rd, 4th to 7th (-13 to -3 dBFS):
63 dB, 71 dB, 80 dB
Acquired bandwidth:
max. 0.8 MHz (good filter)
max. 3.1 MHz (DSP I/O limited)
max. 10 MHz (1K data block)
Maximal data block: 1 Mword x 16 bit

Basic measurements:

Wide-band Spurious Free Dynamic Range of transciever output measured by spectral analyser.
Clock 7x 40 MHz (internal mult.), output frequency 61.504 MHz, 17-bit tuning word 0x383B80000000.
120 MHz artefact from CPLD clock is visible.
Wideband SFDR



Narrow-band view of transceiver output spectra measured by the digital receiver and spectral analyser.
Clock 7x 40 MHz (internal mult.), output frequency 61.504 MHz, 17-bit tuning word 0x383B80000000.
Spikes of n x 50 Hz originate from power net frequency parasitic modulation in receiver, which was solved in next measurement.
Narrowband SFDR



Narrow-band Spurious Free Dynamic Range of receiver.
Measured 100 MHz signal from spectral analyser reference is 31 dB below full-scale of ADC.
Narrowband SFDR of receiver

Compact transciever.
Boards (from top): Receiver, DSP, transmitter, shielding, clock unit.
Transciever photo Home