摘要:
In a quadrature modulation device which receives a pair of carrier signals whose phases are orthogonal to each other and I and Q signals and outputs a modulation signal, a quadrature error between phases of the pair of carrier signals is detected. What is added to the I and Q signals is a pair of such DC voltages that a modulation signal output from the quadrature modulation device when the I and Q signal levels are zero is at a predetermined level. A plurality of such combinations of values of a pair of DC voltages are searched that the signal level of the modulation signal is at the predetermined level when the pair of DC voltages are respectively changed and successively added to the I, Q signals. The quadrature error is calculated from a simultaneous equation having as variables the values in the searched plurality of combinations of values of a pair of DC voltages, the signal level of the modulation signal, and the quadrature error of the carrier signal.
摘要:
A method for measuring radiated power according to the invention, comprises a step of preparing an elliptical mirror having a closed space which has an elliptical spherical shape and which is enclosed by a metal wall surface, the elliptical spherical shape being obtained by rotating an ellipse by a predetermined angle about an axis line passing through two focal points thereof, a step of placing a device under test which can radiate a radio wave, in a position of one of the two focal points in the closed space of the elliptical mirror such that a center of radiation of a radio wave therefrom substantially coincides with the focal point, a step of placing a receiving antenna in an position of an other one of the two focal points in the closed space of the elliptical mirror, and in the closed space of the elliptical mirror, a step of causing the device under test disposed in the position of the one focal point to radiate a radio wave and causing the radio wave radiated from the device under test to be reflected at the wall surface to allow the receiving antenna disposed in the position of the other focal point to receive the radio wave, and a step of measuring total radiated power of the radio wave radiated from the device under test at a measurement end of the receiving antenna in accordance with an output signal from the receiving antenna.
摘要:
The optical signal sampling apparatus and the optical signal monitor apparatus are configured of an optical combiner for combining an optical signal to be sampled and a sampling light pulse with each other and an electroabsorption modulator. The electroabsorption modulator has two optical terminals for inputting/outputting the light and a power supply terminal for applying the electric field to the optical path connecting the two optical terminals, and has such a characteristic that the absorption rate of the light propagating through the optical path changes in accordance with the magnitude of the electric field, the light emitted from the optical combiner is received by one of the two optical terminals, and the absorption rate is increased when the sampling light pulse is not incident while the absorption rate is decreased when the sampling light pulse is incident. Further, the apparatuses include a DC power supply for applying a predetermined DC voltage to the power supply terminal and an optical separator for selectively emitting the optical signal component to be sampled, of the optical signals emitted from another of the two optical terminals.
摘要:
An electroabsorption optical modulator used as a sampling element has two optical terminals and a power supply terminal, the two optical terminals are used to input and output light, and the power supply terminal imparts an electric field to an optical path connecting the two optical terminals. The electroabsorption optical modulator has a characteristic in which an absorption index is changed with respect to the light beam propagating through the optical path according to a level of the electric field. A monitoring (synchronization sampling) object optical signal is input into one of the two optical terminals of the electroabsorption optical modulator. A predetermined direct-current voltage exhibiting a high absorption index for the monitoring (synchronization sampling) object optical signal is imparted to the power supply terminal of the electroabsorption optical modulator. A sampling optical pulse is input into another of the two optical terminals of the electroabsorption optical modulator through a photocoupler. The absorption index for the monitoring (synchronization sampling) object optical signal is lowered by a mutual absorption saturation characteristic of the electroabsorption optical modulator, and synchronization sampling of the monitoring (synchronization sampling) object optical signal is performed to supply an optical signal from the other of the two optical terminals of the electroabsorption optical modulator through the photocoupler. The mutual absorption saturation characteristic is generated when the sampling optical pulse is input into the other of the two optical terminals.
摘要:
A test apparatus main body (101) mounted in a single housing (100) has a connection unit (17), a common bus (4), terminal control units (5,6), measurement units (7,8), and a total control unit (9). The connection unit (17) can connect at least two terminals (1,2) of identical or different type of communication systems. The terminal control units (5,6) output test signals including signals that respectively control the terminals (1,2) which can be connected to the connection unit (17) based on predetermined test programs according to the type of communication systems, and measurement instructions, which are supplied via the common bus (4). The measurement units (7,8) perform measurements designated by the measurement instructions upon reception of response signals which are output from the terminals (1,2) in response to the test signals from the terminal control units (5,6). The total control unit (9) supplies, in advance, the predetermined test programs according to the type of communication systems and outputs the measurement instructions at predetermined timings to the terminal control units (5,6).