摘要:
A robust downlink timing synchronization method for reducing the influence of initial frequency offset and ensuring the timing synchronization in a low signal-to-noise ratio interval in an LTE system, which includes: step 1: a receiving terminal continuously storing time domain signal sequences of M PSS transmission periods; step 2: performing narrowband filtering on the time domain signal sequences of the M PSS transmission periods; step 3: performing down-sampling on data obtained after the filtering; step 4: performing sliding differential mirror correlation on the down-sampling data of an mth PSS transmission period to obtain a correlation value of an ith instant; step 5: superposing correlation results to obtain a superposition result; and step 6: determining whether the superposition result has an obvious peak interval; if yes, completing capturing the primary synchronization signal, and obtaining timing information according to a position of a maximum correlation peak; otherwise, returning to step 1.
摘要:
A switching power supply includes a rectifier circuit, a converter, a detecting unit, a control unit, a switching unit, and a protection unit. The rectifier circuit is used for rectifying an input voltage into a first direct current voltage. The converter is configured for generating a first current according to the first direct current voltage. The detecting unit is used for generating a detected voltage according to the first current. The control unit is configured for generating a control signal. The switching unit is used for enabling the converter, and conducting the first current to the detecting unit when receiving the control signal. The protection unit is configured for shunting the first current with the detecting unit when the first current becomes a large current surge. The control unit stops generating the control signal when determining that the detected voltage is equal to or higher than a predetermined value.
摘要:
A data acquisition card, an extension control system of data acquisition cards and method thereof are disclosed. The method includes: presetting a card address for each data acquisition card, and presetting a channel address for each data channel in the data acquisition card; the data acquisition card generating a corresponding card address signal after receiving a card beat signal from a user circuit, and judging whether the data acquisition card is gated; and if the data acquisition card is gated, then generating a corresponding channel address signal after receiving a channel beat signal from the user circuit, and gating a data channel corresponding to the channel address signal. The data acquisition card, the extension control system of the data acquisition cards and method thereof have the strong extensibility and high stability.
摘要:
A power supply protection device for an electric appliance includes a switching circuit for establishing an electrical connection to receive an external voltage from the external power supply and output the external voltage to the electric appliance, a detecting circuit for disabling the switch circuit to break the electrical connection when determining the external voltage is equal to or higher than a predetermined value, and an alert circuit for generating an alert signal when the electrical connection is broken and outputting the alert signal to a user.
摘要:
A data acquisition card, an expansion control system for a data acquisition card and a method thereof are disclosed. The method includes: a card address is preset for each data acquisition card, a channel address is preset for each data channel in the data acquisition card; the data acquisition card generates a corresponding card address signal after receiving a card beat signal from a user circuit, and judges whether the data acquisition card is selected; if the data acquisition card is selected, it generates a corresponding channel address signal after receiving a channel beat signal from the user circuit, and selects the data channel corresponding to the channel address signal. The data acquisition card, the expansion control system for the data acquisition card and the method thereof have powerful expansibility and high stability.
摘要:
Disclosed is a robust downlink timing synchronization method in an LTE system, which includes: step 1: a receiving terminal continuously storing time domain signal sequences of M PSS transmission periods; step 2: performing narrowband filtering on the time domain signal sequences of the M PSS transmission periods; step 3: performing down-sampling on data obtained after the filtering; step 4: performing sliding differential mirror correlation on the down-sampling data of an mth PSS transmission period to obtain a correlation value of an ith instant; step 5: superposing correlation results to obtain a superposition result; and step 6: determining whether the superposition result has an obvious peak interval; if yes, completing capturing the primary synchronization signal, and obtaining timing information according to a position of a maximum correlation peak; otherwise, returning to step 1. The present invention effectively reduces the influence of initial frequency offset and ensures the timing synchronization in a low signal-to-noise ratio interval. The present invention has fine utility under the receiving conditions where the initial frequency offset is not compensated and the channel transmission environment is unknown, and has good robustness.
摘要:
A power supply protection device for an electric appliance includes a switching circuit for establishing an electrical connection to receive an external voltage from the external power supply and output the external voltage to the electric appliance, a detecting circuit for disabling the switch circuit to break the electrical connection when determining the external voltage is equal to or higher than a predetermined value, and an alert circuit for generating an alert signal when the electrical connection is broken and outputting the alert signal to a user.