Steadong D-808 is a full band. In addition to the FM/MW/SW band, it also supports FM RDS. Like Shanjin 909X, the time information information sent by the radio, the name of the radio, the program name, etc. You can also use this. The machine time is synchronized with the radio time, and it also supports unilateral bands and aviation bands. It can be said that 808 is a model of ZUI &39; Quan in the same volume.
The circuit design of 808 is not as simple as most DSP machines. In people''''''''''''''''s impression, there are very few DSP components, and fewer people make people lose their desire to play. However, the motherboard of 808 is full of traditional analog devices. Because there is no drawing information, I just guess its circuit structure based on experience. First look at the main chips of it. The core of the DSP is SI''''''''''''''''s 4735-D60, and D60 is a model that supports RDS decoding. The frequency adjustment head actually uses the traditional CD7358, the power amplifier uses HWD4863, and the logic switch of the double op amp LM358, 74HC as the short -wave front -end slot switch, as well as short -bands and double grid pipes. So boldly speculate that its circuit principle, the frequency adjustment section 7358 This front -end chip is still a traditional connection method. After the two consecutive tuning output, the intermediate frequency is entered into 3560 for DSP audio demodulation, three -dimensional sound decoding and RDS decoding. Although the 3560 can also be directly connected to the antenna, the performance of 7358 must be stronger than it, so only DSP is used to process the part of the intermediate frequency. The part is very reasonable. The amplitude part is a highlight. In the circuit analysis of Desheng 330, I saw De Sheng only use short -wave input bands and field tubes. The 808 is even more particular. After the antenna is input, it is the four -slot LC LC tuning frequency and the dual -grid field tube high. This design is also the classic circuit structure of the simulator, which can ensure good frequency selection characteristics and sufficient gain. It is the key to obtaining high signal -to -noise ratios and receiving performance. After the signal of high release, the DSP is sent to the DSP for further amplification and digital processing. The power amplifier chip 4863 is a high -performance chip of the BTL and OTL mode electronic switching. The peripheral components are small, the distortion is very low, and the hearing is good.
The sensitivity is better than the Desheng PL660, which is almost the same as 880. In selectivity, the D-808 uses a DSP chip to play a role in the intermediate frequency filter, which provides up to 11 bandwidth(6 kinds of medium waves, 6 types of unilateral), Even more than De Sheng PL880. But the size of this machine is smaller than those radios.
Black D808
Gray D808 radio