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Signal number Signal name Symbol Meaning 1 Standby (戒備) No. 1 signal is an advisory signal for when there is a tropical cyclone centred within about 800 kilometres of Hong Kong. If strong winds are not expected within 24 hours, the issuance of the signal may be delayed.
Signal No. Meaning TCWS #1 winds of 30–60 km/h (19–37 mph; 16–32 kn) are prevailing or expected to occur within 36 hours: TCWS #2 winds of 61–120 km/h (38–74 mph; 33–64 kn) are prevailing or expected to occur within 24 hours: TCWS #3 winds of 121–170 km/h (75–105 mph; 65–91 kn) are prevailing or expected to occur within 18 ...
A signal generator is one of a class of electronic devices that generates electrical signals with set properties of amplitude, frequency, and wave shape. These generated signals are used as a stimulus for electronic measurements, typically used in designing, testing, troubleshooting, and repairing electronic or electroacoustic devices, though it often has artistic uses as well.
In Hong Kong, the Hong Kong Observatory raised typhoon signal 1 at 12.40pm on November 8, and Signal 3 on November 9 at 3.40pm. [57] [58] The cross harbour swimming race in Victoria Harbour scheduled for November 10 was cancelled. [59] In Macau, typhoon signal 1 was raised on November 8 on 11am followed by Signal 3 on November 9 at 11pm. [60]
Using MF signaling, the originating telephone switch sends a start signal to seize the line, taking the circuit off-hook. The terminating office acknowledges the seizure with a ready state by responding with a wink start signal, which is a momentary off-hook condition. The originating office then sends address information to the terminating switch.
The network analyzer needs a test signal, and a signal generator or signal source will provide one. Older network analyzers did not have their own signal generator, but had the ability to control a stand-alone signal generator using, for example, a GPIB connection. Nearly all modern network analyzers have a built-in signal generator.
DTMF keypad layout Combination of 1209 Hz and 697 Hz sine waves, representing DTMF "1" The DTMF telephone keypad is laid out as a matrix of push buttons in which each row represents the low frequency component and each column represents the high frequency component of the DTMF signal. The commonly used keypad has four rows and three columns ...
A completely different approach to function generation is to use software instructions to generate a waveform, with provision for output. For example, a general-purpose digital computer can be used to generate the waveform; if frequency range and amplitude are acceptable, the sound card fitted to most computers can be used to output the generated wave.