Abstract: It is possible to easily set the operation of a spectrum analyzer. The spectrum analyzer receives a signal to be measured. The spectrum analyzer includes a display device (28) having a display screen for displaying the signal to be measured with a vertical axis representing a measurement value (power) of the signal to be measured and a horizontal axis representing frequency. Furthermore, a touch panel is provided on the display screen of the display device (28). When a user of the spectrum analyzer touches a point 32a (f0, P0) on the display screen, peak search is performed to detect a maximal value of the measurement value of the signal to be measured in a range of the vicinity of the touched point (frequency f1 to f2, power P1 to P2) (wherein f1=f0??f, f2=f0+?f, P1=P0??P, P2=P0+?P). Thus, it is possible to easily set the range for performing the peak search.

Abstract: A signal measuring device controls the width of a signal for controlling frequency sweep, in accordance with a signal to be measured. The signal measuring device includes a local oscillator (10) for generating a local signal, a mixer (12) for mixing a signal to be measured with the local signal; a frequency sweep section (14) for sweeping the frequency of the local signal, and a sweep control section (30) for terminating the sweep when the presence section of the signal to be measured has terminated. The signal to be measured is a carrier in a burst and the spectrum of the carrier is to be measured. The width of the presence section of the signal to be measured may be changed. Even if changed, it is possible to control the width of the signal for controlling the frequency sweep, in accordance with the signal to be measured since the sweep is terminated when the presence section of the signal to be measured has terminated.

Abstract: A spectrum analyzer having an improved local oscillator for use in a digital step sweep is capable of minimizing a dynamic spurious response which is inverse proportional to a unit step time in the step sweep. The local oscillator includes a random clock delay which provides a random clock to a direct digital synthesizer to incorporate random timings in a time length of the unit step time for sweeping the local oscillator. In another aspect, the local oscillator includes a sweep step number control which maximizes the number of steps in the step sweep to ultimately decrease the dynamic spurious response.

Abstract: A spectrum analyzer in which automatic setting of parameters such as band width is done by the analyzer without manual operator input and noise measurements are determined and displayed to the operator. This is accomplished by an input signal being supplied to a frequency mixer via an input variable attenuator. The frequency of the input signal is mixed with the frequency of a local signal from a frequency sweep generator. The mixed signal is then supplied to a band pass filter and the output of the filter is amplified by an amplifier. The frequency of the amplified output is mixed with the frequency of a local signal from a local oscillator by a frequency mixer. The intermediate frequency signal is taken out by a band pass filter and the output is detected by a detector. The detected output is converted into a digital signal by an A/D converter after passing through a low pass filter and the digital signal is stored in a buffer memory. A CPU sets an attenuation amount.

Abstract: A measuring device and method use a spectrum analyzer. The spectrum analyzer comprises a display screen controlled by a processor on which a spectrum of an input signal is displayed in a frequency region on a half portion of the display screen and a noise level at a frequency associated with the input signal is displayed in a time region on another half portion of the display screen.

Abstract: An improved local oscillator for use in a digital step sweep is capable of minimizing dynamic spurious which is an inverse of the unit step time T.sub.step. The local oscillator includes a random clock delay 12 which provides a random clock 12.sub.rndclk to the DDS 40 to modify a time length of the unit step time T.sub.step for sweeping the local oscillator to be random.

Abstract: A spectrum analyzer converts frequencies of an input signal using a local signal from a local signal generator, detects the frequency converted outputs, and sweeps the frequencies of said local signal generated by said local signal generator, to obtain a frequency-based output, wherein said local signal generator comprises a digital direct synthesizer for incrementing the output frequency for every input clock, a variable frequency oscillator for outputting an oscillation output as said local signal and a phase locked loop for controlling the oscillation frequency of said variable frequency oscillator using the output of said digital direct synthesizer as a reference signal.

Abstract: The object of a spectrum analyzer of present invention is to increase a frequency stability and SPAN probability. A voltage control oscillator is rendered to a locked state based on a frequency as a reference frequency output from a direct digital synthesizer. Thereafter, the voltage control oscillator performs a sweep operation for a signal output therefrom, based on a frequency error to which a ramp signal is added by an adder, that is, based on the reference frequency output from the direct digital synthesizer.