Kenwood TS-990S manual Advanced AGC control, fusing together digital and analog

HF/50MHz TRANSCEIVER TS-990S DSP/IF filter

Equipped with dedicated DSP for the main receiver, sub-receiver, and band scope

Extensive interference elimination and noise reduction functions

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

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.)

IF filter bandwidth variability

You can vary DSP filter 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.

Band elimination filter function

The filter 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-		Band Elimination Filter
tion for operations		0
such as dampen-	(dB)	-20

WIDTH

You can avoid neighboring signals by varying the bandpass width.

SHIFT

If the interference is on one side only, you can shift the central frequency without changing bandwidth.

ing interference	Amplitude	-40
		-60
signals, even if it
		-80
cuts down some of
		-1,000 -500	0	500 1,000

For main IF DSP, transmission unit	For sub IF DSP, every kind of signal processing	For band scope
ADSP-21363 clock @333 MHz	ADSP-21369 clock @260 MHz	ADSP-21363 clock @333 MHz

WIDTH

Intended

signal

SHIFT

Target

signal

the target signal. Frequency (Hz)

The noise blanker function (NB1/NB2) is equipped with digital/analog 2 format

Equipped with an analog noise blanker (NB1) which is considered effective against weak noise, and a

Advanced AGC control, fusing together digital and analog
The reception sound quality of SSB and CW is not						significant role as well. The opinion of many of our
solely determined by audio frequency and filter						fans that “even for long periods of time they never
delay properties. AGC characteristics play a very						get tired of listening” is due to the characteris-
								tics of Kenwood’s AGC. The
IF AGC control block diagram
					SOFT-ATK		Demod	TS - 990S goes a long way
					CONT
RX IF	IF ADC		Digital NB				RX Audio	in helping further refine the
Analog					AGC DET	AGC DET		Kenwood sound by innovating
AGCV	AGCV DAC	AGC DET						not only the AGC control algo-
				IF Filter
		OUT Band		AutoManual Notch				rithm on the DSP but also the
				Band Elimination Filter
		ATK/REL
		Manager						analog AGC unit as well.

Exacting chassis design for realizing quality sound

IF filter A/B/C one-touch switch instantly

It is possible to preset a maximum of three IF filter bandwidths and switch instantly at any time. Set for narrow or wide,

such a function is convenient for com- petitions requiring quick operations.

IF notch

You can eliminate overpowering interference signals with a notch filter and catch intended weak signals.

You can switch between the IF auto notch and the
manual notch that	IF Manual Notch BW 400 Hz / 800 Hz

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.

DSP-based noise reduction function (NR1/NR2)

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.

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.

ϕ77 mm	Top plate oscillation
Built-in speaker	simulation example

can be changed		0
manually, depend-	(dB)	-20
	Amplitude	-40
ing on the state of
		-60
interference.
		-80
		-1,000 -500	0	500 1,000
			Frequency (Hz)

<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.

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