摘要:
The present invention relates to synchronization circuitry that is used to synchronize an asynchronous received RF message with a transmitted RF message. In one embodiment of the present invention, the synchronization circuitry includes at least one counter, which is used to associate timing of the asynchronous received RF message with a receive count value, and associate timing of the transmitted RF message with a transmit count value. A time delay between occurrence of the receive count value and the transmit count value provides accurate timing for the start of the transmitted RF message.
摘要:
A system and method are provided for quickly measuring the Root Mean Square (RMS) value of digital quadrature signals (I, Q) input to a Wideband Code Division Multiple Access (W-CDMA) transmitter. In general, in a W-CDMA transmitter such as that in a Universal Mobile Telecommunications System (UMTS), multiple channels are combined to provide the digital quadrature signal (I, Q) input to the transmitter. The RMS value of the digital quadrature signal (I, Q) may be determined using a number of consecutive samples of the digital quadrature signal (I, Q) over a period corresponding to mutually orthogonal segments of the spreading codes used for the transmitted channels. As a result of the mutual orthogonality of the segments of the spreading codes, a residual error of the RMS measurement is equal to zero, thereby providing an accurate RMS measurement in much less time than required by traditional RMS measurement schemes.
摘要:
A communications receiver and a method for receiving and processing information transmitted on either a wide band carrier or a narrow band carrier having In-phase-Quadrature-phase (IQ) modulation, comprising, detecting a portion of the spectrum wide enough to encompass the wide band carrier (BW), converting the wide band carrier to baseband in I and Q components, each component having a bandwidth of BW/2, converting the I and Q components into further I and Q components to form components II, IQ, QI, and QQ of bandwidth equal to BW/4, where each of the sub-bands may contain a portion of the originally transmitted information. Operating in wideband mode, each of the components/is separately processed to extract portions of the originally transmitted information, and operating in a narrowband mode, each of the components containing information is separately processed within the narrow band transmitted carrier to extract portions of the originally transmitted information. The components are then recombined to reconstruct the originally transmitted information.
摘要:
Local oscillator apparatus comprising communication signal terminals (LNA IN, LNA INX; RF OUT,RF OUTN) for a communication signal, especially in a receiver or a transmitter, and a controlled frequency oscillator (204; 404) for producing a local oscillator signal. The local oscillator also includes a reference frequency generator (210; 410) and a feedback loop (208;408) for selecting and adjusting the frequency (fVCO) of the local oscillator signal relative to the frequency (fxtal) of said reference frequency signal. A first frequency divider (205; 405) divides the frequency of the local oscillatr signal by a first division factor (M) to produce a conversion signal, where the frequency (FILO) of said conversion signal is at least approximately equal to the frequency (fRF) of the communication signal, and conversion means (202,203; 402, 403) responsive to the conversion signal converts between said communication signal and a base-band signal. A second frequency divider (206;406) divides the frequency of the local oscillator signal by a second division factor (N) and is connected in the feedback loop, where the first division factor (N) is different to the second division factor (M) and the ratios between said first and second division factors (M/N, N/M) are fractional.
摘要:
Apparatus 20,30,40,50 for receiving and processing a wanted Radio Frequency signal comprises a radio frequency to intermediate frequency down-conversion stage 20 for receiving the wanted radio frequency signal and out-putting a complex intermediate frequency signal; an analogue to digital converter 30 for converting the complex intermediate frequency signal to a digital complex intermediate signal; an intermediate frequency to base-band down-conversion stage 40 for receiving the digital complex intermediate frequency signal and out-putting a digital complex base-band signal; and a complex notch filter 50 for receiving the digital complex base-band signal and out-putting a notch filtered digital complex base-band signal wherein the complex notch filter 50 substantially filters out a small portion of the base-band signal centred about a first, non-zero, frequency while substantially passing a corresponding portion of the base-band signal centred about a second frequency having the same magnitude but opposite sign to the first frequency.
摘要:
The detailed description described embodiments of highly efficient power management systems configurable to simultaneously generate various output voltage levels for different components, sub-assemblies, and devices of electronic devices, sub-systems, and systems. In particular, the described embodiments include power management systems that substantially reduce or eliminate the need for inductors, large numbers of capacitors, and complex switching techniques to transform an available voltage level from a system power source, such as a battery, to more desirable power supply voltages. Some described embodiments include a charge pump that uses only two flying capacitors to simultaneously generate multiple supply outputs, where each of the multiple supply outputs may provide either the same or a different output voltage level. The described embodiments also include efficient power management systems that flexibly provide highly accurate voltage levels that are substantially insensitive to the voltage level provided by a system power source, such as a battery.
摘要:
A method of defining a quasi iso-gain supply voltage function for an envelope tracking system is disclosed. The method includes a step of capturing iso-gain supply voltage values versus power values for a device under test (DUT). Other steps involve locating a minimum iso-gain supply voltage value, and then replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value. The method further includes a step of generating a look-up table (LUT) of iso-gain supply voltage values as a function of input power for the DUT after the step of replacing the iso-gain supply voltage values with the minimum iso-gain supply voltage value for corresponding output power values that are less than an output power value corresponding to the minimum iso-gain supply voltage value.
摘要:
A tunable receiver system uses programmable notch filters to identify available channel pairs for transmitting and receiving data via a femtocell base station. In addition, one of the programmable notch filters may be used to suppress infiltration of the transmit path signal into the receiver path of the receiver device. The other programmable notch filter may be used to suppress a blocker signal identified by the receiver device.
摘要:
A digital log gain to digital linear gain multiplier is disclosed. The digital log gain to digital linear gain multiplier includes a log gain splitter adapted to split a log gain input into an integer log part and a remainder log part. A log scale-to-linear scale converter is adapted to output a linear gain value in response to the integer log part and the remainder log part. A gain multiply circuit is adapted to multiply a digital signal by the linear gain value to output a gain-enhanced digital signal.
摘要:
An open loop envelope tracking system calibration technique and circuitry are proposed. A radio frequency power amplifier receives a modulated signal. An envelope tracker power converter generates a modulated power amplifier supply voltage for the radio frequency power amplifier based on a control signal derived from the modulated signal. A first output power and a second output power of the radio frequency power amplifier are measured when the control signal is respectively delayed by a first delay period and a second delay period. A sensitivity of the output power of the radio frequency power amplifier is near a maximum near the first delay period and the second delay period. The first delay period and/or the second delay period are adjusted until the first output power substantially equals the second output power. The first delay period and the second delay period are used to obtain a calibrated fine tuning delay offset.