User's Manual

85894_M&R_TA7650C_A 2-2
2.2 Main module
The main module consists of the main board and the modulator module.
The modulator module is plugged into the main module.
2.2.1 Main board
The main board consists of DSP section, Audio section, DAC/ADC interface, BITE interface,
I/O interface, Ethernet controller and memory section.
2.2.1.1 DSP
The heart of the board is a digital signal processor (DSP-IC42) running firmware for all
interactions with it’s peripherals. The DSP has implemented functionality to:
• Modulate a given input signal with AM and D8PSK, and generate I/Q baseband data.
• Interface with the Audio Codec responsible for converting audio signals and BITE
measurements.
• Interface with the D/A converters converting baseband signals to RF/IF
• Interface with the A/D converters converting the demodulated output signal from
analog to digital.
• Implement an adaptive linearization loop for improving Power Amplifier (PA)
performance
• Interact with the ethernet controller for external control and data exchange
• Implement a user interface, interact with user actions and provide visual feedback
through display and LED’s.
2.2.1.2 Audio
The audio codec(IC 13) will receive and transmit digital audio data from/to the DSP. The
audio codec itself will be responsible for:
• Amplifying, mixing and converting microphone signals to digital codes
• Amplifying, mixing and converting analogue input line(s) to digital codes
• Conduct analogue BITE measurements and convert these to digital values
The audio from the audio codec is routed to an audio amplifier (IC 38 –Monitor, IC11-
Headphone)
2.2.1.3 Baseband DACs
A dual DAC(IC 17) will interface with the DSP. This DAC will :
• Perform high-quality DA conversion of the digital signal to analog I/Q-signal
• Provide a good match between the I/Q channels.
2.2.1.4 PA Feedback ADC
Two ADC’s will demodulated output signal. The output of this will be fed into the DSP,
which in turn will use this data for adaptive pre-distortion of the PA and output signal for
monitoring purposes.