HC01 Wired Double key Handset

What is the principle of HC01 Wired Double Key Handset to achieve calls?

As a wired double-key phone, the process of HC01 Wired Double Key Handset to achieve calls involves multiple technical links, including signal modulation, transmission, reception and decoding. The following is a detailed analysis of the call principle of HC01 phone.

1. Basics of wired telephone communication
Wired telephone communication is a communication method that transmits sound signals through physical lines (such as telephone lines). During the communication process, the sound signal is first converted into an electrical signal, then transmitted to the other party's phone through the telephone line, and finally the electrical signal is restored to a sound signal for human ears to receive. This process involves multiple key steps, including sound collection, conversion, transmission, reception and restoration.

2. Hardware structure of HC01 phone
As a terminal device for wired telephones, the hardware structure of HC01 phone mainly includes microphone, speaker, baseband chip, intermediate frequency chip, radio frequency chip, telephone line interface and double-key operation panel.
Microphone: used to collect the user's sound signal and convert it into an analog electrical signal.
Speaker: used to restore the received electrical signal to a sound signal for the user to listen to.
Baseband chip: responsible for processing baseband processing tasks such as digitization, compression, encryption, and encoding of sound signals.
Intermediate frequency chip: in some cases, it may involve converting baseband signals into intermediate frequency signals suitable for transmission.
Telephone line interface: used to connect telephone lines to achieve physical transmission of signals.
Two-key operation panel: provides user operation interfaces such as answering, hanging up, and speed dialing.
3. Call principle
Sound collection and conversion: When the user speaks to the microphone of the HC01 phone, the microphone converts the sound signal into an analog electrical signal. This analog electrical signal is then sent to the baseband chip for further processing.
Signal digitization and compression: In the baseband chip, the analog electrical signal is first converted into a digital signal. This process is usually achieved through an analog-to-digital converter (ADC) to convert the continuous analog signal into a discrete digital signal. Digital signals have the advantages of higher anti-interference ability and easier processing. In order to reduce the demand for transmission bandwidth and storage space, digital signals also need to be compressed. Compression algorithms can remove redundant information from signals while trying to maintain the original quality of the signal.
Signal encoding and encryption: After digitization and compression, the signal needs to be encoded for transmission on the telephone line. The encoding process converts the digital signal into a format suitable for transmission and may add some additional information to improve the reliability and efficiency of transmission. In order to ensure the security of communication, some phones may also encrypt the signal to prevent the signal from being eavesdropped or tampered with during transmission.
Signal transmission: The encoded signal is transmitted to the other phone through the telephone line. As a physical transmission medium, the telephone line carries the task of signal transmission. During the transmission process, the signal may be subject to various interferences, but these interferences can usually be suppressed or compensated by appropriate signal processing technology.
Signal reception and decoding: After the other phone receives the signal, it first decodes it to restore the signal in the transmission format to a digital signal. Then, the digital signal is decompressed and restored to the original analog electrical signal. The analog electrical signal is sent to the speaker and restored to a sound signal for the user to listen to.
Functional realization of double-button operation: The double-button design of the HC01 phone is usually used to realize common functions such as speed dialing, answering/hanging up calls, etc. When the user presses a certain button, the phone will perform the corresponding operation according to the preset program. When the answer button is pressed, the phone will automatically enter the call state; when the speed dial button is pressed, the phone will automatically dial according to the preset number.

4. Special technical considerations
Although the HC01 phone is relatively simple in technology as a wired phone, some special technical issues still need to be considered in actual applications.
Signal attenuation and compensation: There will be signal attenuation problems in the transmission process of the telephone line, which needs to be compensated by devices such as signal amplifiers or equalizers.
Noise suppression: During the call, it may be disturbed by background noise. In order to improve the call quality, the phone usually uses noise suppression technology to reduce the impact of noise.
Echo cancellation: During the call, if there is a delay difference in the signal transmission between the two phones, an echo phenomenon may occur. Echo cancellation technology can effectively eliminate this echo phenomenon and improve the clarity of the call.