Abstract: A high speed receiver is provided using two parallel processing paths to enable rapid variable gain control. The parallel processing paths include a first processing path using a high resolution Discrete Fourier Transform (DFT), and a second processing path using a reduced DFT requiring fewer samples than the high resolution DFT. An initial sample of the data is processed using the second processing path with the reduced DFT by comparing a Fourier transform of the initial sample with predetermined threshold values. As a result of the comparison of the Fourier transform of the initial sample with the predetermined threshold values, a gain determination block determines whether a requirement exists for gain ranging. If gain ranging is needed, the gain of the data signal is adjusted and the gain ranging process repeats.

Abstract: A system and method for implementing dynamic spur avoidance in a high speed receiver environment is provided. For a plurality of radio frequency (RF) input signal ranges, a range of intermediate frequency (IF) signals and a noise floor for each IF signal is determined. An identification of spurs that will affect the noise floor is also determined from a look up table for each range of the RF inputs. A frequency plan that sets local oscillator and constituent oscillator signals is selected such that the IF signals generated from the RF input will avoid lower order spurious responses of the identified spurs within the IF signal range.

Abstract: An instrument is provided for measuring a noise figure with significant flexibility. The instrument includes a noise source (306) and a vector network analyzer (VNA) (300). The VNA (300) includes an external connector port (302) for removable connection of the noise source (306). The noise source (306) can be connected to the VNA backplane port (302), or directly to a DUT (350). The DUT (350) can be connected to both VNA test ports (310,314) if the noise source (306) is connected to port (302), or only to test port (314) if the noise source (306) is directly connected to the DUT. A receiver connected to the test port (314) includes a downconverter (324) providing an IF signal through either a narrowband IF channel (350) or a wideband IF channel (352) for providing both wideband and narrowband power measurements enabling fast accurate measurement of a noise figure.

Abstract: A vector network analyzer (VNA) is provided with three test ports and an integration of hardware and software to make an integrated set of measurements for two and three port devices. The integrated capability allows for fast, versatile measurements that benefits, in accuracy and convenience, from sharing of data and resources with other measurements. The VNA includes a first signal source which is selectively connectable through reflectometers to two of the three VNA test ports. A second signal source provides connection through a third reflectometer to a third test port to enable full vector error corrected 3-port S-parameters measurements to be made. The two signal sources, along with software configuration of the VNA to operate in a non-ratioed mode provides for measuring second and third order intercept measurements. The two signal sources and software also enable the VNA to be used to make frequency translation measurements of a mixer including accurate frequency translation group delay measurements.

Abstract: A method is provided for eliminating the source harmonic component from VNA measurements of the output of a device under test (DUT). A standard vector measurement, GHx, is first measured from the DUT using the VNA. The value GHx is composed of two elements, the DUT's harmonic response to a fundamental input from the source, and the DUT's linear response to the harmonic input from the source. The harmonics from the source which are linearly passed by the DUT, GNx, are then measured with the VNA. The output harmonic generated by the DUT, Hx, is then calculated using vector subtraction according to the equation Hx=GHx−GNx. The output harmonic Hx will then be free from source harmonic components.

Abstract: A method for determining the harmonic response of a device under test (DUT) to the input fundamental frequency component of an input signal is performed on a vector network analyzer. A first response of the DUT at the harmonic frequency is obtained by measuring the linear response of the device at the harmonic frequency of interest after appropriate normalization. A second response of the DUT is obtained by measuring the response of the DUT at the harmonic frequency to an input which comprises a source input fundamental with its harmonic components after appropriate normalization. The harmonic response of the DUT to the source input fundamental alone is computed from the first and second responses. Such computations allow the harmonic response of the DUT to be measured free of stimulus source harmonics, so that overall harmonic measurement accuracy and dynamic range is enhanced.

Abstract: A method for determining the harmonic phase response ∠POx of a device under test (DUT) is performed on a vector network analyzer (VNA). The phase ∠GN1 of the transfer response GN1 of the DUT at the fundamental frequency is determined from VNA measurements after appropriate normalization. The corrected phase ∠GHxC of the harmonic transfer response of the DUT is determined from VNA measurements after appropriate normalization. The corrected phase ∠GHxC of the harmonic transfer coefficient GHx is subtracted from a predetermined phase reference ∠refx to obtain a difference ∠refx−∠GHxC, and the phase ∠GN1 of the transfer coefficient GN1 at the fundamental frequency is added to the difference ∠refx−∠GHxC to obtain the harmonic phase offset ∠POx. For the second and third harmonics using a clipping waveform, the phase reference ∠refx is 180°.

Abstract: A dual-mode multiple signal source/local oscillator module is capable of operating in either an independent offset mode or a common offset mode. The module includes first and second coarse frequency sources, a first signal generator coupled to the first coarse frequency source, a second signal generator, and an offset switch coupled to the second signal generator. The offset switch connects the second signal generator to either the first coarse frequency source in the common offset mode, or the second coarse frequency source in the independent offset mode. Operation of the sources in the common offset mode provides the benefits of dynamic tracking which include reduction of receiver IF phase noise and spurious signal content, improved receiver IF settling speed, and higher measurement accuracy.

Abstract: A receiver configured to measure phase change (.DELTA..phi.) in a signal transmitted from a microwave signal source, such as a cell site for cellular telephones, the transmitted signal including a carrier signal (F.sub.1) added to a modulation signal (F.sub.MOD), the receiver providing the phase change measurement (.DELTA..phi.) without further reference to the modulation signal (F.sub.MOD). Utilizing (.DELTA..phi.), distance from the transmitter can be calculated. The receiver includes one or more mixers for receiving the transmitted signal from the cell site and downconverting relative to an intermediate frequency signal (F.sub.IF) to produce an IF mixed signal including a sum IF mixed signal (F.sub.IF +F.sub.MOD) and a difference IF mixed signal (F.sub.IF -F.sub.MOD). The receiver then further includes components to demodulate the IF mixed signal to provide the modulated signal (F.sub.MOD) and the phase change measurement (.DELTA..phi.) with tracking of the intermediate frequency signal (F.sub.IF).