Kenwood TS-990SHF manual HF/50MHz Transceiver TS-990S

The newly developed narrow-band High-IP roofing filter shows its true value by cutting adjacent unwanted signals

You can realize high C/N levels by dividing high frequencies using the newly developed VCO frequency division 1st local oscillator

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 final bandpass settings. Of course, manual switch- ing is possible as well.

The TS-990S Local Oscillator Circuit is an independent configuration 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

TS-990S MAIN Local OSC C/N

Roofing

Filters

270Hz

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.

Offset Frequency [Hz]

Main receiver 1st Local Oscillator C/N main receiver characteristic example (20m/160m)

TS-990S MAIN BAND FRONT-END

1st Mixer

throughthrough

500Hz

2.7kHz

6kHz

15kHz

DDS IC AD 9951

Comes equipped with ±0.1ppm TCXO, which combines high stability and energy saving

1st Mixer

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.