1, airpods second generation has a wired charging version and wireless charging version, in addition to the charging method, there is no difference between the two versions of the headset, both use H1 chip, and support voice activated Siri. airpods use tips: airpods can not connect to iPhone, it may be a bug in the mobile phone system, you can upgrade the system; airpods support the hearing aid function, which is convenient for users with disabilities to use the earphones.
2, the chip inside the Apple charging cable is used for decoding. In other words, it is used for system information interaction, mutual confirmation and authentication. The cottage of the data line can only cottage some of the functions, the full function of the chip is not cottage.
3, Apple Bluetooth headphones airpods second generation wired charging version and wireless charging version in the use of methods, configuration, appearance and other aspects of no difference, the only difference is the charging method, wireless charging box version of the price is more expensive, airpods second generation support voiceWake Up Siri, with a built-in H1 chip, can bring smaller access latency and better sound quality.
4, different charging methods The wired charging version of the charging box only supports the connection of lightning data line charging, and the wireless charging version is equipped with a charging box that supports wireless charging, which can be easily charged by simply placing it on the wireless charging board. Compared with the first generation of AirPods, the second generation is equipped with a new H1 headset chip, and the fastest switching between associated devices is twice the previous, and the fastest connection when making and receiving calls is five times the previous.
5, Apple wired earphone original heelThe sound quality of the original chip is the same. The sound quality of Apple's Lightning wired headphones is also limited by the chip built into the interface.
Because it is relatively difficult to extract coherent carrier from FSK signal, incoherent demodulation method is used in practical engineering applications. Under the condition of the same bit error rate, the signal-to-noise ratio required for incoherent demodulation is only 1~2dB higher than that for coherent demodulation. There are many kinds of incoherent demodulation, such as: demodulation method based on adaptive filter, differential detection algorithm, AFC loop demodulation method, overZero detection method, envelope detection method, etc.
fsk demodulation the carrier frequency of the baseband signal needs to be converted into an AM wave with two amplitudes. In order to detect the desired frequency signal from the AM wave output of the tuned circuit without distortion, the time constant RC must be properly selected. In the design, one frequency of two different frequency carriers is set to resonant frequency, and the demodulation of AM wave can be carried out by using envelope detection circuit.
means that a sine wave of one frequency is sent when ""), and a sine wave of another frequency is sent when the space sign (means" & ") is sent. According to '()! &! Advice, callSK decoding chip , support MPEG-4 video decoding and playback. It integrates 32bit DSP Core with 16bit ADC and 18bit DAC, providing a cost-effective solution for multimedia products such as portable MP3 players and foreign language learning machines.
2, Philips series. Philips decoding chips generally use the BGA packaging process, and the domestic technology in this area is quite limited, in addition, because Philips decoding chips need to work together with another control chip circuit, so the product cost is high. thereforeManufacturers using Philips decoding chips tend to be positioned in the middle and high price range, such as MPIO and IRIVER, two Korean MP3 specialists. Telechips' TCC730/TCC731 series.
3, if we must evaluate the best MP3 decoding chip on the market, then it is undoubtedly Philips chip. The decoding chips of the Philips family have been known in the industry for their "full functionality, good sound quality and high price".
4, Ruixin products digital audio and video processing chip RK26XX series chipsIt is a digital audio and video processing chip that supports MPEG-4 video decoding and playback function, and is made of 0.18 micron process, which can be applied to portable MP3 player products with MP4 playback function. 5, South Korea ECT company's SKYLARK chip, the current domestic button machine are used, but does not support WMA, the price is similar to STMP3410, the function is more complete.