2 TRANSMISSION
2.1 Kenwood Traditional Transmitting Circuitry
The tradition of high quality audio technology that users rely on Kenwood to deliver is produced by combining analog and digital technologies that Kenwood has nurtured thus far. The DSP controls modulation and determines the sound quality and analog circuits convey and amplify the signal cleanly.
2.1.1 IF Circuits
The first IF transmit signal that is output at 24 kHz from the DSP and the DA converter is converted to 10.695 MHz in a dedicated IC for the mixer. The second IF signal at 10.695 MHz passes an IF filter of 6 kHz bandwidth at which undesired frequency components outside the pass bandwidth are attenuated before the signal is amplified. Then, the second IF signal passes to the ALC circuit that controls the output power to a stable level. After that, the signal goes through the gain control circuit that corrects the minutely small differences in gain from band to band, and the signal enters the mixer that is commonly used in TX and RX, and is converted to the third IF of 73.095 MHz. The signal passes the gain control circuit that adjusts the signal to the necessary gain level according to the specified power level. Then, the signal passes the filter that eliminates spurious components before going into the mixer circuit that converts the signal to the desired transmit frequency. Also, delicate gain control is done, such as decreasing the gain of the amplifier while the key is not depressed in CW mode. By means of these processes, a
2.1.2 FET Final Circuit
The final amplifier of the
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