|
BPC (time Signal)
BPC is the callsign of a time signal broadcasting from the BPC Shangqiu Low-Frequency Time-Code Radio Station, cooperatively constructed by the National Time Service Center of the Chinese Academy of Sciences and Xi'an Gaohua Technology Co., Lt beginning April 25, 2002. BPC transmits a time signal on 68.5 kHz, which can be used for synchronizing radio controlled clocks. The transmission site is situated near Shangqiu, Henan Province at . BPC broadcasts at 90 kW for 20 hours per day, with a 4-hour break from 05:00–09:00 China Standard Time daily (21:00–01:00 UTC). BPC includes both a conventional amplitude-modulated time code transmitted during the first 400 of each second, and an additional phase-modulated spread-spectrum time code transmitted during the last 600 ms of each second, about which little is known. Time code BPC transmits the time every 20 seconds, using an amplitude-modulated binary code sent at 2 bits per second. Each 20-second block en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, audible signals (even signal guns) have limited range. Busy seaports used a visual signal, the dropping of a ball, to allow mariners to check the chronometers used for navigation. The advent of electrical telegraphs allowed widespread and precise distribution of time signals from central observatories. Railways were among the first customers for time signals, which allowed synchronization of their operations over wide geographic areas. Dedicated radio time signal stations transmit a signal that allows automatic synchronization of clocks, and commercial broadcasters still include time signals in their programming. Today, global navigation satellite systems ( GNSS) radio signals are used to precisely distribute time signals over much of the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Time Service Center
The National Time Service Center (NTSC; ) has the task of generating, maintaining and broadcasting standard time in China. It is located in Xi'an, Shaanxi, China. Its predecessor was the Shaanxi Astronomy Observatory of the Chinese Academy of Sciences, which was established in 1966. In March 2001, the Observatory was renamed to National Time Service Center of the Chinese Academy of Sciences. NTSC includes short-wave ( BPM) and long-wave ( BPL) standard time and frequency radio stations. And in 2007, low-frequency ( BPC) time signal station began trial broadcasting from Shangqiu Shangqiu ( zh, ), Postal romanization, alternately romanized as Shangkiu, is a city in eastern Henan province, Central China. It borders Kaifeng to the northwest, Zhoukou to the southwest, and the provinces of Shandong and Anhui to the northeast .... References Research institutes of the Chinese Academy of Sciences 1966 establishments in China Education in Xi'an Time in China {{Sci-org-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Academy Of Sciences
The Chinese Academy of Sciences (CAS; ) is the national academy for natural sciences and the highest consultancy for science and technology of the People's Republic of China. It is the world's largest research organization, with 106 research institutes, 2 universities, 71,300 full-time employees, and 79 thousand graduate students. The Chinese Academy of Sciences has historical origins in the Academia Sinica during the Republic of China (1912–49), Republican era and was formerly also known by that name until the 1980s. The academy functions as the national scientific think tank and academic governing body, providing advisory and appraisal services on issues stemming from the national economy, Social change, social development, and science and technology progress. It is headquartered in Beijing, with affiliate institutes throughout China. It has also created hundreds of commercial enterprises, Lenovo being one of the most famous. The academy also runs the University of Scienc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shangqiu
Shangqiu ( zh, ), Postal romanization, alternately romanized as Shangkiu, is a city in eastern Henan province, Central China. It borders Kaifeng to the northwest, Zhoukou to the southwest, and the provinces of Shandong and Anhui to the northeast and southeast respectively. Its population was 7,816,831 inhabitants as of the 2020 Chinese census whom 2,831,814 lived in the built-up (''or metro'') area made up of two urban districts (Liangyuan and Suiyang) and Yucheng county now being conurbated. Shangqiu and surrounding area was an important base for the Shang dynasty (c. 1600 – c. 1046 BC), and the city itself was established more than three millennia ago. Shangqiu has grown significantly in recent years. It is located at an important location at the junction of several major railways, making it a major regional transportation hub. History The history of Shangqiu ("Hills of Shang") is closely related to the very beginning of Chinese history. The tradition dates back to the Three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henan
Henan; alternatively Honan is a province in Central China. Henan is home to many heritage sites, including Yinxu, the ruins of the final capital of the Shang dynasty () and the Shaolin Temple. Four of the historical capitals of China, Luoyang, Anyang, Kaifeng and Zhengzhou, are in Henan. While the province's name means 'south of the river', approximately a quarter of the province lies north of the Yellow River. With an area of , Henan covers a large part of the fertile and densely populated North China Plain. Its neighboring provinces are Shaanxi, Shanxi, Hebei, Shandong, Anhui, and Hubei. Henan is China's third-most populous province and the most populous among inland provinces, with a population of over 99 million as of 2020. It is also the world's seventh-most populous administrative division; if it were a country by itself, Henan would be the 17th-most populous in the world, behind Egypt and Vietnam. People from Henan often suffer from regional discrimination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China Standard Time
The time in China follows a single standard UTC offset, time offset of UTC+08:00, where Beijing is located, even though the country spans five geographical time zones. It is the largest sovereign nation in the world that officially observes only one time zone. The nationwide standardized time is named Beijing Time (BJT; ) domestically and China Standard Time (CST) internationally. Daylight saving time has not been observed since 1991. China Standard Time (UTC+8) is consistent across Mainland China, Hong Kong Time, Hong Kong, and Macau Standard Time, Macau. It is also equivalent with Time in Taiwan, Taiwan, Philippine Standard Time, Philippines, Singapore Standard Time, Singapore, Time in Brunei, Brunei, most of Time in Mongolia, Mongolia, Time in Malaysia, Malaysia, Irkutsk Time of Russia, Time in Australia, Western Australia, and Time in Indonesia, Central Indonesia. History In the 1870s, the Shanghai Xujiahui Observatory was constructed by a French Catholic missionary. In 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude Modulation
Amplitude modulation (AM) is a signal modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the instantaneous amplitude of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its Phase (waves), phase, as in phase modulation. AM was the earliest modulation method used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century beginning with Roberto Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. This original form of AM is sometimes called double-sideband amplitude modulation (DSBAM), because the standard method produces sidebands on either side of the carrier frequency. Single-sideband modulation uses bandpass filters to eliminate one of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Modulation
Phase modulation (PM) is a signal modulation method for conditioning communication signals for transmission. It encodes a message signal as variations in the instantaneous phase of a carrier wave. Phase modulation is one of the two principal forms of angle modulation, together with frequency modulation. In phase modulation, the instantaneous amplitude of the baseband signal modifies the phase of the carrier signal keeping its amplitude and frequency constant. The phase of a carrier signal is modulated to follow the changing signal level (amplitude) of the message signal. The peak amplitude and the frequency of the carrier signal are maintained constant, but as the amplitude of the message signal changes, the phase of the carrier changes correspondingly. Phase modulation is an integral part of many digital transmission coding schemes that underlie a wide range of technologies like Wi-Fi, GSM and satellite television. However it is not widely used for transmitting analog audio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YouTube
YouTube is an American social media and online video sharing platform owned by Google. YouTube was founded on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim who were three former employees of PayPal. Headquartered in San Bruno, California, it is the second-most-visited website in the world, after Google Search. In January 2024, YouTube had more than 2.7billion monthly active users, who collectively watched more than one billion hours of videos every day. , videos were being uploaded to the platform at a rate of more than 500 hours of content per minute, and , there were approximately 14.8billion videos in total. On November 13, 2006, YouTube was purchased by Google for $1.65 billion (equivalent to $ billion in ). Google expanded YouTube's business model of generating revenue from advertisements alone, to offering paid content such as movies and exclusive content produced by and for YouTube. It also offers YouTube Premium, a paid subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decibel
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a Power, root-power, and field quantities, power or root-power quantity on a logarithmic scale. Two signals whose level (logarithmic quantity), levels differ by one decibel have a power ratio of 101/10 (approximately ) or root-power ratio of 101/20 (approximately ). The strict original usage above only expresses a relative change. However, the word decibel has since also been used for expressing an Absolute scale, absolute value that is relative to some fixed reference value, in which case the dB symbol is often suffixed with letter codes that indicate the reference value. For example, for the reference value of 1 volt, a common suffix is "#Voltage, V" (e.g., "20 dBV"). As it originated from a need to express power ratios, two principal types of scaling of the decibel are used to provide consistency depending on whether the scaling refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Msbit
In computing, bit numbering is the convention used to identify the bit positions in a binary number. Bit significance and indexing In computing, the least significant bit (LSb) is the bit position in a binary integer representing the lowest-order place of the integer. Similarly, the most significant bit (MSb) represents the highest-order place of the binary integer. The LSb is sometimes referred to as the ''low-order bit''. Due to the convention in positional notation of writing less significant digits further to the right, the LSb also might be referred to as the ''right-most bit''. The MSb is similarly referred to as the ''high-order bit'' or ''left-most bit''. In both cases, the LSb and MSb correlate directly to the least significant digit and most significant digit of a decimal integer. Bit indexing correlates to the positional notation of the value in base 2. For this reason, bit index is not affected by how the value is stored on the device, such as the value's byte ord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterfall Plot
Waterfall plots are often used to show how two-dimensional phenomena change over time. A three-dimensional ''spectral waterfall plot'' is a plot in which multiple curves of data, typically spectra, are displayed simultaneously. Typically the curves are staggered both across the screen and vertically, with "nearer" curves masking the ones behind. The result is a series of "mountain" shapes that appear to be side by side. The waterfall plot is often used to show how two-dimensional information changes over time or some other variable such as rotational speed. Waterfall plots are also often used to depict ''spectrograms'' or ''cumulative spectral decay'' (CSD). Uses * The results of spectral density estimation, showing the spectrum of the signal at successive intervals of time. * The delayed response from a loudspeaker or listening room produced by impulse response testing or MLSSA. * Spectra at different engine speeds when testing engines. See also * Loudspeaker acoustics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
