Abstract:
A low-jitter delay locked loop having an expanded phase locking range without the necessity of setting the initial delay is provided. The loop is to be supplied by a system clock and includes a pulse generator receiving the system clock for generating a first pulse signal and a second pulse signal in response to a triggering signal, a delay device receiving the system clock for providing a delayed clock in response to a control signal, a frequency-reducing device for frequency-reducing the system clock into a first clock in response to the first pulse signal and frequency-reducing the delayed clock into a second clock in response to the second pulse signal, and a comparator for comparing the first and second clocks to generate the control signal.
Abstract:
A signal-testing device used with a tester for testing a first signal and a second signal includes a selected signal generator receiving first signal and second signal for generating a selected signal the state of which is changed when first signal and second signal are in specific states, and a signal selector for selectively outputting one of first and second signals in response to the selected signal state. The present invention also provides a signal-testing method including steps of a) generating a selected signal having a plurality of pulses in response to a first signal and a second signal, b) obtaining a plurality of time differences between times when two inter-adjacent respective pulses respectively reach a specific voltage, c) obtaining a plurality of absolute values between two inter-adjacent respective time differences, and d) obtaining a phase difference by dividing by 2 an average value of the absolute values.
Abstract:
A phase lock loop (PLL) clock generator with programmable frequency and skew is provided in the present invention, in which frequency of clock signals generated can be dynamically changed and skew of the clock signals generated can be dynamically adjusted by a computer program. Also, the signal skew due to the change of loading can be compensated. Therefore, the PLL clock generator based on a closed-loop configuration can better control the skew of clock signals to provide higher stability and durability to the system.
Abstract:
A monitoring camera has a base, a camera module and a casing. The base has a parapet formed on the base. The parapet has a memory slot and at least one pair of guide slots formed oppositely on the parapet. Each guide slot has a notch extending toward the bottom of the parapet. The casing corresponds to and covers the parapet and has at least one pair of guide protrusions formed on the casing. The guide protrusions respectively engage corresponding guide slots. When unscrewing the casing, the guide protrusions will correspondingly move and be mounted in the notches and the memory slot is accessible. Therefore, the casing need not to be completely detached from the base to allow a removable memory to be installed or removed easily.
Abstract:
A monitoring camera has a base, a camera module and a casing. The base has a parapet formed on the base. The parapet has a memory slot and at least one pair of guide slots formed oppositely on the parapet. Each guide slot has a notch extending toward the bottom of the parapet. The casing corresponds to and covers the parapet and has at least one pair of guide protrusions formed on the casing. The guide protrusions respectively engage corresponding guide slots. When unscrewing the casing, the guide protrusions will correspondingly move and be mounted in the notches and the memory slot is accessible. Therefore, the casing need not to be completely detached from the base to allow a removable memory to be installed or removed easily.
Abstract:
A clock recovery circuit for generating an output signal that is synchronized with an input signal. The clock recovery circuit includes a charge pump, a first filter, an oscillator, a switch circuit, and a second filter. When the charge pump operates, the switch circuit will disconnect the first filter from the oscillator. Additionally, when the charge pump stops operating, the switch circuit will connect the first filter and the oscillator such that the oscillator adjusts a frequency or phase of the output signal according to the output voltage of the first filter.
Abstract:
An active hybrid circuit for a full duplex channel generates a duplicated voltage at the current output stage to reduce the energy of the transmitter transmitted to the receiver. The active hybrid circuit cancels the energy of the transmitter transmitted to the receiver when it is operated in a full duplex channel with high-speed transmission. The active hybrid circuit for full a duplex channel comprises a transmit digital-to-analog converter for generating an analog transmit signal, a receive analog-to-digital converter for receiving an analog receive signal, a duplicated voltage digital-to-analog converter for generating a corresponding duplicated voltage according to the analog transmit signal of the transmit digital-to-analog converter, and a plurality of signal combiners for subtracting the duplicated voltage from the analog transmit signal to cancel the influence of analog transmit signal to the analog receive signal.
Abstract:
A device and method for measuring the jitters of phase locked loop signals. A phase lead or phase lag relationship between an input signal and an output signal of a phase locked loop is found. According to the phase relationship and using multiplexers, a first phase difference signal and a second phase difference signal are re-routed to a subtraction unit and produces a jitter-level output signal. The jitter-level output signal represents the absolute value of the difference of pulse width between the first phase difference signal and the second phase difference signal.
Abstract:
An analog-to-digital data converter converts an input signal to corresponding digital signals. The data converter includes two sets of comparison units arranged in an interlaced sense to alternatively analyze the input signal, generate digital signals corresponding to the result of comparing the input signal and reference signals. Each of the comparison units has a positive output and a negative output, and the digital signal is generated by the negative output and the positive output of the comparison units in a differential way. When the comparison units of one set are performing auto-zeroing, the comparison units of the other set perform the data conversion to generate corresponding digital signals.
Abstract:
An analog-to-digital data converter converts an input signal to corresponding digital signals. The data converter includes two sets of comparison units arranged in an interlaced sense to alternatively analyze the input signal, generate digital signals corresponding to the result of comparing the input signal and reference signals. Each of the comparison units has a positive output and a negative output, and the digital signal is generated by the negative output and the positive output of the comparison units in a differential way. When the comparison units of one set are performing auto-zeroing, the comparison units of the other set perform the data conversion to generate corresponding digital signals.