摘要:
A signal reception apparatus in the spread spectrum communication system requires only a small amount of circuitry and consumes a small amount of electric power. A quadrature detector decomposes received signals into in-phase components and quadrature components, and supplies them to a complex-type matched filter. The complex-type matched filter de-spreads the in-phase components and the quadrature components and sends them to a multi-path selector. The multi-path selector selects, from among the received de-spread signals, multiple paths having high levels of signal electric powers and sends the received signals of the selected paths to multiple phase correction blocks. Analog operation circuits calculate phase errors of the received signals of two successive pilot symbol blocks for each path. An analog operation circuit corrects the phases of the received signals of the information symbol block that has been received between the two successive pilot symbol blocks. A rake combiner synchronously combines the phase-corrected de-spread received signals of each path.
摘要:
This invention reduces electric power consumption of a CDMA communication system receiver while it is in the wait mode. A received spread spectrum signal is demodulated in multiplication means into baseband signals Ri and Rq, and inputted into a complex matched filter. This filter is intermittently driven by supply voltage control means to perform acquisition of received signals. When an electric power calculation circuit detects the output of the filter to reach a peak equal to or greater than a predetermined value, the received signals undergo acquisition by controlling n number of correlators 26-1 to 26-n to work by a correlator controlling circuit. Moreover, de-spreading is performed. The outputs from each correlator 46-1 to 26-n are given to a RAKE combiner and demodulated by the RAKE by a combining and demodulating circuit.
摘要:
A fast spread spectrum communication system is provided, having fewer circuits and requiring fewer PN codes to be assigned to a user. A series of digital data to be transmitted, is divided into 4-bit frames. The 4-bit data of each frame is divided into the first through fourth elements in a predetermined order. The first complex number is constructed by the first and second elements, and the second complex number is determined according to the value of the third and fourth elements. The spectrum of the data to be transmitted is spread by multiplying these complex numbers. Four matched filters despread a received signal by different combinations of PN codes stored in a receiver. The first through fourth elements are recovered according to the outputs of the matched filters.
摘要:
A matched filter with reduced electric power consumption is disclosed. The matched filter circuit power consumption is reduced by stopping the electric power supply to an unnecessary circuit since input signal is partially sampled just after an acquisition. Since the spreading code is 1 bit data string, the input signal sampled and held is branched out into the signal groups "1" and "-1" by a multiplexer. The signals in each groups are added in parallel by a capacitive coupling, and the electric power is supplied in the circuit intermittently.
摘要:
The present invention has an object to provide an inverted amplifying circuit with improved accuracy of output and reduced electric power consumption. In an inverted amplifying circuit according to the present invention, a MOS switch is connected between pMOS and nMOS of a CMOS inverter and between balancing resistances. The MOS switch is opened when the inverted amplifying circuit does not work.
摘要:
In one aspect, the present invention provides a low power consumption matched filter. The signal received at an input terminal is input to a shift register having stages equal to the spread code length number after conversion into digital signals in an A/D converter. The outputs of the shift register stages are input to XOR circuits set corresponding to each stage, so that XOR operations are performed between the outputs and corresponding spread code bits d1 to dN. The outputs of the XOR circuits are analogously added in an analog adder and output from an output terminal. In another aspect, a filter circuit uses an analog operation circuit to prevent lowered operational accuracy caused by residual charge. Input analog signals successively undergo sampling and holding in sample-and-hold circuits, are multiplied by coefficients stored in a shift register by multiplication circuits, and added in an addition circuit. Sample data transmission error storage is prevented by shifting coefficients in the shift register. Sample-and-hold circuits and multiplication circuits are formed by analog operation circuits, and each include a switch for canceling the residual charge. The sample-and-hold circuits and multiplication circuits normally working are refreshed sequentially by providing circuits for replacing their function. The addition circuit is refreshed in the same way.
摘要:
A matched filter contains a plurality of auxiliary sampling and holding circuits in addition to a main sampling and holding circuit containing multiple unit sampling and holding circuits. An auxiliary sampling and holding circuit is used to hold an input voltage, which would ordinarily be held by a unit sampling and holding circuit, when the unit sampling and holding circuit is being refreshed. By holding a part of the analog input voltage in the auxiliary sampling and holding circuits, refreshing is performed without decreasing the overall calculation speed.
摘要:
An object of the present invention is to provide a matched filter circuit of small size and consuming low electric power. Paying attention that a spreading code is a 1 bit data string, an input signal is sampled and held as an analog signal along the time sequence, classified into "1" and "-1" and the classified signals are added in parallel by capacitive coupling in a matched filter circuit according to the present invention.
摘要:
A highly accurate vector absolute-value calculation circuit uses analog processing and minimal hardware. Signal voltages corresponding to an I component (real number part) and a Q component (imaginary number part) are input to a first absolute-value calculation circuit 13 and a second absolute-value calculation circuit 14 through terminals 11 and 12, respectively, and they are each converted into absolute-value signals. The component I absolute-value and component Q absolute-value are compared in a comparison circuit 20. According to the result, the larger absolute-value signals are output to an input capacitor 23 of a neural computation circuit, and the smaller absolute-value signals are output to an input capacitor 24 by controlling multiplexers 21 and 22. The capacity ratio of a feedback capacitor 26 of a neural computation circuit and input capacitors 23 and 24 is 11:10:5. The complex number absolute-value calculated by the following formula is output from an output terminal 27. ##EQU1##
摘要:
The present invention provides a weighted addition circuit for sampling, holding and performing weighted addition by a circuit smaller than a conventional one. In the weighted addition circuit of to the present invention, a capacitive coupling is connected to a plurality of switches which are further connected only to an input voltage. A voltage is held and a weight is added in the capacitive coupling.