Filter
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The newly developed narrow-band High-IP roofing filters show their true
value by cutting adjacent unwanted signals
High C/N levels are realized by dividing high frequencies using
the newly developed VCO frequency division 1st local oscillator
Comes equipped with ±0.1 ppm TCXO,
which combines high stability and energy saving
through
through through
0/6/12/18 dB
270 Hz
500 Hz
6 kHz
15 kHz
2.7 kHz
1st Mixer
Roofing
Filters
RF BPF
ATT
Pre Selector
Pre Amp Post Amp
TS-990S MAIN BAND FRONT-END
DDS IC AD 9951
Mode Phantom load Start-up time
Stand-by
power saving
Or less
0.5 W
Approx.
40 seconds
Normal Approx. 20 W
Approx.
5 seconds
Roofing filter-characteristic example BW=500 Hz
Roofing filter-characteristic example BW=270 Hz
1st Mixer
CH1 B/R log MAG
CH2 B/R log MAG
IF BW 100 Hz SWP 8.6 sec
SPAN 2 kHz
10 dB/ REF 0 DB
10 dB/ REF 0 DB
SPAN 100 kHz
CH1 B/R log MAG
CH2 B/R log MAG
IF BW 100 Hz SWP 8.6 sec
SPAN 3.5 kHz
10 dB/ REF 0 DB
10 dB/ REF 0 DB
SPAN 100 kHz
TS-990S MAIN Local OSC C/N
Phase Noise [dBc/Hz]
Offset Frequency [Hz]
100
-160
-150
-140
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
1,000 10,000 100,000
14.1 MHz
1.83 MHz
82.78～
92.48 MHz
96.48～
107.48 MHz
115.48～
128.992 MHz
127.48～
138.992 MHz
PLL PLL
AMP
AMP
Divider
1/N
Main reception unit
1st Local Oscillator Block Diagram
DDS
1.8/3.5/5M
7M
14/18/21/24M
...
N=10
...
N=8
...
N=4
(other than these,
DDS Direct)
Main receiver 1st Local Oscillator C/N Main receiver characteristic
example (20m/160m)
The transceiver uses the down-conversion method
on all amateur bands, and features five types of
High-IP roofing filter. Narrow bandpass widths
selectable are 500 Hz and 270 Hz for CW opera-
tion, 2.7 kHz for SSB and 6 kHz and 15 kHz,
which are suitable for AM/FM. These filters are
automatically selected in tandem with DSP-based
settings. Of course, manual switching is possible
as well.
The TS-990S Local Oscillator Circuit is an indepen-
dent configuration that combines the main receiver
and VCO Frequency Division/DDS, the sub-receiver,
DDS, transmitter and conventional PLL, with the
targeted signal system. The newly developed VCO
frequency division format is used for the 1st local
oscillator of the main receiver. The device achieves
favorable 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
oscillator and increasing the C/N ratio.
The standard equipment includes a TCXO (Temperature-
Compensated Crystal Oscillator), which stabilizes frequencies
at ±0.1 ppm 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 Lot 6.
Power consumption in stand-by energy-saving mode is less
than 0.5 W. A BNC connector on the rear panel provides
10 MHz reference I/O.
7
HF/50MHz TRANSCEIVER TS-990S
Main receiver