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The newly developed narrow-band High-IP roofi ng fi lter shows its true
value by cutting adjacent unwanted signals
The transceiver uses a down-conversion method
for all amateur band reception, and features five
types of High-IP roofing filter. Narrow bandpass
widths selectable are 500 Hz and 270 Hz for CW
operation, 2.7kHz for SSB and 6kHz and 15kHz,
which are suitable for AM/FM. These filters are
automatically selected in tandem with DSP-based
fi nal bandpass settings. Of course, manual switch-
ing is possible as well.
Roofing
Filters
270Hz
TS-990S MAIN BAND FRONT-END
500Hz
500Hz
1st Mixer
2.7kHz
through
through
6kHz
6kHz
Pre Amp
Post Amp
15kHz
1st Mixer
CH1 B/R log MAG
10 dB/ REF 0 DB
CH2 B/R log MAG
10 dB/ REF 0 DB
IF BW 100 Hz
SWP
8.6 sec
SPAN
2 kHz
SPAN 100 kHz
Roofi ng fi lter-characteristic example BW=270Hz
CH1 B/R log MAG
10 dB/ REF 0 DB
CH2 B/R log MAG
10 dB/ REF 0 DB
IF BW 100 Hz
SWP
8.6 sec
SPAN 3.5 kHz
SPAN 100 kHz
Roofi ng fi lter-characteristic example BW=500Hz
HF/50MHz TRANSCEIVER TS-990S
You can realize high C/N levels by dividing high frequencies using
the newly developed VCO frequency division 1st local oscillator
The TS-990S Local Oscillator Circuit is an independent
confi guration that combines the main receiver and VCO
Frequency Division/DDS Direct, the sub-receiver and
DDS Direct, and the transmitter and conventional PLL,
with the targeted signal system. The newly developed
VCO frequency division format is used for the 1st lo-
cal oscillator of the main receiver. The device achieves
favourable C/N characteristics that rival the DDS direct
format, and relatively spurious-free local oscillation
signals that are characteristic of the PLL format, by
oscillating and dividing the VCO at higher frequencies
than the intended frequency. It is possible to convert it
to 1st IF in a pure state without leaking the target signal
as noise by reducing static noise from the local oscilla-
tor and increasing the C/N ratio.
Main reception unit
1st local oscillator block diagram
PLL
DDS
DDS IC AD 9951
Comes equipped with ±0.1ppm TCXO, which combines high stability and
energy saving
The standard equipment includes a TCXO (Temperature-
Compensated crystal Oscillator), which stabilizes frequen-
cies at ±0.1ppm as the standard signal source. Unlike OCXO
(Oven Controlled crystal Oscillator), which requires warm-up
time, this device can start up quickly even from the power-off
position, while maintaining a high level of stability. It is in
compliance with European energy-saving standard Lot6.
Power consumption in stand-by energy-saving mode is less
than 0.5 W. A BNC connector on the rear panel provides
10MHz reference I/O.
TS-990S MAIN Local OSC C/N
0
14.1MHz
-10
1.83MHz
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
100
1,000
10,000
Offset Frequency [Hz]
Main receiver 1st Local Oscillator C/N main receiver characteristic
example (20m/160m)
AMP
Divider
1/N
82.78
115.48
AMP
... N=10
1.8/3.5/5M
92.48MH
128.992MH
... N=8
PLL
7M
... N=4
14/18/21/ 24M
96.48
127.48
(other than these,
107.48MH
138.992MH
DDS Direct)
Mode
Phantom load
Start-up time
Stand-by
Or Less
Approx.
power saving
0.5W
40 seconds
Approx.
Approx.
Normal
20W
5 seconds
Main receiver
100,000
7
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