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The history of walkie talkies

The history of walkie talkies

2018-04-07

The technology of walkie talkies first emerged in the panicked 1920s, born in laboratories. A quirky inventor named John Kermode had a wild idea to achieve automatic sorting of postal documents. At that time, every idea about the application of electronic technology made people

Unveiling Police Wireless Interphone

Unveiling Police Wireless Interphone

2017-09-11

Police wireless walkie talkies are specialized walkie talkies for wireless communication business contacts between eight departments: public security, procuratorial, court, judicial, security, customs, military, and armed police. In order to ensure the security of communication services for the special departments mentioned above, the national radio management department has specially planned several sets of frequencies for their use, ranging from 350 to 390MHz. Among them, 350MHz to 370MHz are mainly used for public security systems. This frequency range is referred to as the 350MHz low-end in the industry.

The phase-locked loop and voltage controlled oscillator (VCO) generate emissions

The phase-locked loop and voltage controlled oscillator (VCO) generate emissions

2017-09-11

The phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) produce the phase-locked loop and voltage controlled oscillator (VCO) generates emissions

How to test the non-linear distortion coefficient of walkie talkie audio

How to test the non-linear distortion coefficient of walkie talkie audio

2017-09-11

The non-linear distortion coefficient of audio refers to the ratio of the total effective value of each harmonic component of the audio output by the transmitter after demodulation to the effective value of the entire signal when a standard test tone (frequency modulation frequency of 1KHz, distortion coefficient less than 1%, amplitude of the modulated signal frequency offset reaches the rated frequency offset) is added to the audio input end for modulation. Can be measured using a nonlinear distortion meter. According to technical requirements, the nonlinear distortion coefficient of the base station is usually less than 7%, and that of the mobile station is not more than 10%.

2015 Wanhua Interphone Brand Promotion Conference - Shenyang First Station Splendid Opening

2015 Wanhua Interphone Brand Promotion Conference - Shenyang First Station Splendid Opening

2017-09-06

On July 26, 2015, Fujian Wanhua Electronic Technology Co., Ltd. held a brand promotion event for walkie talkies at the Shenyang Country Garden Maritim Hotel in Shenyang. In this meeting, Shenyang Tianyu Ruize Science and Trade Co., Ltd. was authorized as the general agent of Wanhua brand walkie talkies in Liaoning Province. Gather colleagues and suppliers from all walks of life in security to witness this moment together!

The advantages of digital walkie talkies over analog walkie talkies

The advantages of digital walkie talkies over analog walkie talkies

2018-01-03

In terms of design technology, wireless walkie talkies can be divided into analog walkie talkies (commonly known as traditional walkie talkies) using analog communication technology and digital walkie talkies designed using digital technology. Analog walkie talkies modulate stored signals onto the transmission frequency of walkie talkies, while digital walkie talkies digitize speech information and propagate it in digital coding form, that is, all modulation on the transmission frequency of walkie talkies is digital. Digital walkie talkies have significant advantages such as strong speech anti-interference ability, clear speech, high confidentiality, narrower channel bandwidth, and stronger data transmission ability.

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