Advanced Agc Control Via If Digital Processing - Kenwood TS-590SG Manual

DSP 04
As for ADCs and DACs, the best combination of models are selected to suit the type of signal processed, especially for the
IF input section, high-performance ADCs designed for high-end audio with dynamic range of 114 dB are used.
Both the ADCs and DACs have two analog input/output channels per device and the DSP has four input channels and six
output channels of signals.
As indicated above, the DSP processes many signals concurrently. This delivers a wide variety of benefits including the
capability to independently set volume levels of speakers, signal levels from external terminals and USB audio, and to
trigger the VOX circuit through the microphone and the external terminal at the same time.
However, handling so many signals simultaneously puts a heavy load on the 32-bit floating point DSP, though it operates
at the clock frequency of 221 MHz. The DSP needs to be able to handle many different signals, while performing not only
basic functions including IF-AGC, digital IF filtering, and demodulation, but also more advanced functions such as noise
reduction and manual notch filtering. To achieve this goal, we have introduced a real-time OS to the DSP of the TS-590S/
SG and also paid careful attention to the software configuration to help deliver utmost performance from the OS.
The DSP of TS-590S/SG realizes a variety of functions with its signal processing software that is optimized to fully bring
out the performance of the high-performance hardware of the transceiver.
In the following sections, we will explain the functions made possible with the innovative DSP signal processing technologies.

4.2 Advanced AGC Control via IF Digital Processing

The IF-AGC process during reception can be deemed as an important signal process that determines the quality level of
a product.
TS-870S, TS-2000/X or TS-590S, and TS-990S. Neither of the models come with algorithms that are more innovative than
the IF-AGC process in the advancement of DSP (digital signal processing) or tuning at the analog stage. We discovered
new challenges during each innovation, and struggled to overcome them.
Through repeated innovations while inheriting the tradition, the IF-AGC process can be regarded as the evolution of the
"KENWOOD Tone".
TS-590SG has adopted a sophisticated frequency configuration to switch between down conversion and up-conversion
depending on the conditions. The IF-AGC process is designed in such a way that interfering signals do not affect the target
signals even though the passband width may be widened at the stage before the final passband width of DSP (analog stage).
Figure 4-3 IF-AGC Control Block Diagram
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