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Kenwood continues to provide quality sound trans-
mission that is unattainable through analog circuits.
By installing the world-premiere DSP in the TS-950
and achieving IF AGC control on the TS-870, our
experience has led to the use of three DSP units, one
You can vary DSP lter bandwidth and eliminate ex-
tensive interference depending on use and condition.
You can operate it as a HI CUT/LOW CUT function
in SSB/AM/FM mode, and WIDTH/SHIFT function
in CW/FSK/SSB-DATA transmission mode.
You can eliminate overpowering interference signals
with a notch lter and catch intended weak signals.
You can switch between the IF auto notch and the
manual notch that
can be changed
manually, depend-
ing on the state of
interference.
The lter is capable of varying the stopband band-
width and the amount of loss. When signals that
interfere with the target signal multiply, this is a
convenient func-
tion for operations
such as dampen-
ing interference
signals, even if it
cuts down some of
the target signal.
Equipped with an analog noise blanker (NB1) which
is considered effective against weak noise, and a
digital noise blanker (NB2). Choose the NB1 or
NB2 based on noise type and reception condition.
With NB1, stable noise reduction is possible without
depending on reception bandwidth. NB2 is effective
against noise that cannot be tracked by an analog
noise blanker. Plus, both the NB1 and NB2 can be
used simultaneously with the TS-990S.
The device is also equipped with two types of noise
reduction format—NR1 and NR2. An optimal noise
reduction format is applied to each reception mode
for NR1. And for NR2, SPAC method is applied
which is more effective in CW operation.
It is possible to preset a maximum of three IF lter
bandwidths and switch instantly at any time. Set for
narrow or wide,
such a function is
convenient for com-
petitions requiring
quick operations.
The reception sound quality of SSB and CW is not
solely determined by audio frequency and filter
delay properties. AGC characteristics play a very
IF filter bandwidth variability
on each major block of the TS-990S. By distributing
the signal processing of the main IF, band scope, and
sub-IF, we have realized ample digital signal pro-
cessing power. (FM mode is AF DSP processing.)
signicant role as well. The opinion of many of our
fans that “even for long periods of time they never
get tired of listening” is due to the characteris-
tics of Kenwood’s AGC. The
TS-990S goes a long way
in helping further refine the
Kenwood sound by innovating
not only the AGC control algo-
rithm on the DSP but also the
analog AGC unit as well.
For main IF DSP, transmission unit
ADSP-21363 clock @333 MHz
For sub IF DSP, every kind of signal processing
ADSP-21369 clock @260 MHz
<
Other extensive interference elimination and noise
reduction functions
>
Beat cancel function (BC1/BC2)
The beat cancel function is effective against relatively weak, multiple beats,
whereas the IF auto notch is effective against strong beats.
Audio peak filter
You can vary bandpass width of pitch tone when there are carrier receptions
like CW and FSK. FSK is compatible with mark and space frequencies.
For band scope
ADSP-21363 clock @333 MHz
WIDTH
If the interference is on one side only,
you can shift the central frequency
without changing bandwidth.
You can avoid neighboring
signals by varying the
bandpass width.
Target
signal
Intended
signal
SHIFT
SHIFT
WIDTH
IF filter A/B/C one-touch switch instantly
Band elimination filter function
The noise blanker function (NB1/NB2) is
equipped with digital/analog 2 format
DSP-based noise reduction function (NR1/NR2)
IF notch
The sound quality of the built-in speakers is largely determined by
the chassis structure. With the TS-990S, we have been able to mini-
mize unnecessary chassis vibration through multiple simulations
from the conceptual phase. The Kenwood sound is supported not
only by circuits and DSP but also by exact chassis design.
ϕ
77 mm
Built-in speaker
Top plate oscillation
simulation example
Band Elimination Filter
-1,000
-80
-60
-40
-20
0
-500 0 500 1,000
Amplitude (dB)
Frequency (Hz)
IF Manual Notch BW 400 Hz / 800 Hz
Amplitude (dB)
Frequency (Hz)
-1,000
-80
-60
-40
-20
0
-500 0 500 1,000
IF AGC control block diagram
RX IF
AGC DET
RX Audio
IF Filter
AutoManual Notch
Band Elimination Filter
OUT Band
ATK/REL
Manager
AGCV DAC
Analog
AGCV
IF ADC Digital NB
AGC DET AGC DET
Demod
SOFT-ATK
CONT
Advanced AGC control, fusing together digital and analog
Exacting chassis design for realizing quality sound
Equipped with dedicated DSP for the main receiver, sub-receiver,
and band scope
Extensive interference elimination
and noise reduction functions
9
HF/50MHz TRANSCEIVER TS-990S
DSP/IF filter