Agc Quick Recovery - Kenwood TS-890S In-Depth Manual

One of the factors causing fatigue felt from listening are a momentary signal level overshoot by high-speed attacks. This
phenomenon is inevitable in highlighting weak signals and minimizing distortion on the receiver. However, demodulation
with the phenomenon causes the sound quality to be hard, and the high-processing-speed release setting is of no use.
The sound quality at attacking is based on the comprehensive characteristics including the characteristics of the AGC
amplifier in the analog stage as well as the characteristics of the AGC loops in the preceding and succeeding stages
and the IF filter.
Fig. 33 Comparison of Received CW Waveforms: Conventional Transceiver vs. TS-890S

AGC Quick Recovery

AGC Quick Recovery is a newly-added feature on the TS-890S.
When pulse noise generated by sources such as an electric fence is received, the in-band AGC attacks the pulse noise
to lower the gain of the AGC amplifier. Activation of the in-band AGC suppresses not only the pulse noise but also
the target signal, making it impossible to watch the target signal or resulting in an unpleasant phenomenon where the
volume level of the target signal fluctuates with the repeated pulse noise attacks and releases.
The AGC Quick Recovery is a feature that detects attacks on the pulse noise and restores the gain of the AGC amplifier
instantaneously, thus making it possible to prevent unnecessary suppression of the target signal.
The diagrams below show the in-band AGC input and output of IF signals containing pulse noise. The upper diagram
shows the in-band AGC input and the lower diagram shows the in-band AGC output. AGC Quick Recovery is turned off
in the earlier half of the time axis and signal suppression is observed, while signal suppression is improved when AGC
Quick Recovery is turned on in the later half.
Fig. 34 Input/Output of Signal Containing Pulse Noise to In-band AGC (Quick Recovery OFF in Earlier Half and ON in
KENWOOD Existing Model
Time (s)
Time (s)
Time (s)
Time (s)
Quick Recovery ON
Later Half of Lower Diagram)
DSP 07
31