Modulator, filter, method of controlling gain of filter, and code modulating method

Abstract

A modulator being made small in size, low in costs, low in power consumption, small in heat generation and spurious signals. The modulator includes multipliers ( 101, 102 ) for code-modulating received transmission data (D(n), C(n)), and outputting the modulated data, a control channel gain factor signal generator ( 106 ) for generating a gain control signal, a control channel gain factor signal generator ( 107 ), and weighting coefficient setting signal generators ( 108, 109 ) for receiving the output of the complex-number computing section ( 120 ) and controlling the gains of the raised cosine filters ( 110 to 113 ).

1 . A modulator comprising:
 a code modulating unit to receive transmitted data to perform code modulation on the data and to output code-modulated data;   a gain control signal generating unit to generate a gain control signal; and   a filter unit to receive an output from said code modulating unit to perform bandwidth limitation on the received signal and to output the bandwidth-limited signal,   wherein said filter unit comprises:
 a time-series data generating unit to output time-series data having a plurality of signals containing past inputted signals, and to perform shifting processing; 
 a coefficient setting unit to set a plurality of weighting coefficients in accordance with the value of the output received from the gain control signal generating unit, setting of the weighting coefficients associated with the shifting processing of each of the signals of the time-series data outputted by said time-series data generating unit; and 
 a gain control unit to control a gain according to the plurality of weighting coefficients set by said coefficient setting unit. 
   
     
     
         2 . A modulator comprising:
 a first code modulating unit to receive first transmitted data to perform code modulation on the first transmitted data to output a first code-modulated output;   a second code modulating unit to receive second transmitted data to perform code modulation on the second transmitted data to output a second code-modulated output;   a first gain control signal generating unit to generate a first gain control signal;   a second gain control signal generating unit to generate a second gain control signal;   a first filter unit to receive said first code-modulated output from said first code modulating unit to perform bandwidth limitation on the received output and to output the first bandwidth-limited output;   a second filter unit to receive said second code-modulated output from said second code modulating unit to perform bandwidth limitation on the received output and to output the second bandwidth-limited output; and   an adder to receiver the outputs from said first and second filter units to synthesize received outputs and to output a synthesized output,   wherein said first filter unit comprises:
 a first time-series data generating unit to output first time-series data having a plurality of signals containing past inputted signals, and to perform first shifting processing; 
 a first coefficient setting unit to set a plurality of first weighting coefficients in accordance with the value of the output received from the first gain control signal generating unit, setting of the first weighting coefficients associated with the first shifting processing of each of the signals of the first time-series data outputted by said first time-series data generating unit; and 
 a first gain control unit to control a gain according to the first plurality of weighting coefficients set by said first coefficient setting unit, 
   and wherein the second filter unit comprises:
 a second time-series data generating unit to output second time-series data having a plurality of signals containing past inputted signals, and to perform second shifting processing; 
 a second coefficient setting unit to set a plurality of second weighting coefficients in accordance with the value of the output received from the second gain control signal generating unit, setting of the second weighting coefficients associated with the second shifting processing of each of the signals of the second time-series data outputted by said second time-series data generating unit; and 
 a second gain control unit to control a gain according to the second plurality of weighting coefficients set by said second coefficient setting unit. 
   
     
     
         3 . The modulator according to  claim 2 , wherein said first and second filter units are mounted for every channel multiplexed through encoding. 
     
     
         4 . The modulator according to  claim 1 , wherein one or more of said first filter unit and said second filter unit each comprises an FIR (Finite Impulse Response) filter. 
     
     
         5 . The modulator according to  claim 1 , wherein one or more of said first filter unit and said second filter unit each comprises:
 a shift register section to perform shifting processing on an inputted signal and to output the signal as time-series data made up of a plurality of signals containing past inputted signals;   a plurality of register sections to receive outputs from said gain control signal generating unit and to store and output as weighting coefficients;   a plurality of multipliers to receive the plurality of signals making up said time-series data outputted from said shift register section and the plurality of weighting coefficients outputted from said plurality of registers in synchronization with one another to multiply the signals by the weighting coefficients and to output the products; and   an adder to add the outputs from said plurality of multipliers.   
     
     
         6 . The modulator according to  claim 1 , wherein one or more of said first filter unit and said second filter unit each comprises:
 a shift register section to perform shifting processing on an inputted signal and to output the signal as time-series data made up of a plurality of signals containing past inputted signals;   a shift register to receive a gain control signal from said gain control signal generating unit to perform shifting processing on the received gain control signal and to output the signal as time-series data made up of a plurality of signals containing past gain control signals;   a plurality of first multipliers to multiply each of the plurality of signals outputted from said shift register by each of a plurality of specified coefficients and to output the products as a plurality of weighting coefficients;   a plurality of second multipliers to receive each of the plurality of signals outputted from said shift register section and each of the plurality of weighting coefficients outputted from said first multipliers in synchronization with one another to multiply the signals by weighting coefficients and to output the products; and   an adder to add the outputs from said plurality of second multipliers.   
     
     
         7 . The modulator according to  claim 1 , wherein one or more of said first filter unit and said second filter unit each comprises:
 a shift register section to perform shifting processing on an inputted signal and to output the signal as time-series data made up of a plurality of signals containing past inputted signals;   a plurality of register sections to receive first and second weighting coefficients corresponding to a gain control signal from said gain control signal generating unit to store the weighting coefficients to switch one of first and second weighting coefficients in accordance with the plurality of signal values outputted from said shift register section and to output the weighting coefficients; and   an adder to add the outputs from said plurality of register sections.   
     
     
         8 . The modulator according to  claim 1 , wherein an input signal of said filter section is one-bit data. 
     
     
         9 . A filter to perform bandwidth limitation on code-modulated signals and to output the code-modulated signals comprising:
 a time-series data generating unit to output time-series data made up of a plurality of signals containing past inputted signals, and to perform shifting processing;   a coefficient setting unit to set a plurality of weighting coefficients in accordance with a gain control signal, setting of the weighting coefficients associated with the shifting processing of each of the plurality of signals of the time-series data outputted by said time-series data generating unit; and   a gain control unit to control a gain according to the plurality of weighting coefficients set by said coefficient setting unit.   
     
     
         10 . The filter according to  claim 9 , wherein said filter is an FIR filter. 
     
     
         11 . The filter according to  claim 9 , further comprising:
 a shift register section to perform shifting processing on an inputted signal and to output the signal as time-series data made up of a plurality of signals containing past inputted signals;   a plurality of register sections each storing and outputting each of the plurality of weighting coefficients in accordance with the gain control signal;   a plurality of multipliers to receive each of the plurality of signals making up the time-series data outputted from said shift register section and each of the plurality of weighting coefficients outputted from the plurality of register sections in synchronization with one another to multiply the signals by the weighting coefficients and to output the products; and   an adder to add the outputs from the plurality of multipliers.   
     
     
         12 . The filter according to  claim 9 , further comprising:
 a shift register section to perform shifting processing on an inputted signal to output the signal as time-series data made up of a plurality of signals containing past inputted signals;   a shift register to receive the gain control signal to perform shifting processing on the signal and to output the signal as time-series data made up of a plurality of signals containing past gain control signals;   a plurality of first multipliers to multiply each of the plurality of signals outputted from said shift register by each of a plurality of specified coefficients and to output the products as a plurality of weighting coefficients;   a plurality of second multipliers to receive each of the plurality of signals outputted from the shift register section and each of the plurality of weighting coefficients outputted from said first multipliers in synchronization with one another to multiply the signals by the weighting coefficients and to output the products, and   an adder to add the outputs from said plurality of second multipliers.   
     
     
         13 . The filter according to  claim 9 , further comprising:
 a shift register section to perform shifting processing on an inputted signal and to output the signal as time-series data made up of a plurality of signals containing past inputted signals;   a plurality of register sections to receive and store first and second weighting coefficients according to the gain control signal and to switch the first and second weighting coefficients in accordance with the plurality of signal values outputted from said shift register section; and   an adder to add the outputs from said plurality of register sections.   
     
     
         14 . The filter according to  claim 9 , wherein a signal inputted to said filter is one-bit data. 
     
     
         15 . A filter gain control method for limiting a bandwidth of a code-modulated inputted signal comprising:
 a step of outputting time-series data made up of a plurality of signals containing past inputted signals, and of performing shifting processing;   a step of setting a plurality of weighting coefficients according to a gain control signal, setting of the weighting coefficients associated with the shifting processing of each of a plurality of signals making up the time-series data outputted in the step of outputting the time-series data; and   a step of controlling a gain according to the set plurality of weighting coefficients.   
     
     
         16 . The filter gain control method according to  claim 15 , wherein said filter is an FIR filter. 
     
     
         17 . The filter gain control method according to  claim 15 , wherein the signal inputted to the filter is one-bit data. 
     
     
         18 . A code modulating method comprising;
 a step of receiving and code-modulating a transmitted data and generating the code-modulated data;   a step of generating a gain control signal; and   a step of receiving an output generated in the step of code-modulating and of performing bandwidth-limitation to output the bandwidth-limited data,   wherein the step of receiving the output generated in the step of code-modulating and of performing the bandwidth-limitation to output the bandwidth-limited data comprises:
 a step of outputting time-series data made up of a plurality of signals containing past inputted signals, and of performing shifting processing; 
 a step of setting a plurality of weighting coefficients in accordance with the value of the output received from the gain control signal generating unit, setting of the weighting coefficients associated with the shifting processing of each of a plurality of signals making up the time-series data outputted in the step of outputting the time-series data; and 
 a step of controlling a gain according to the plurality of weighting coefficients set in the step of setting the plurality of weighting coefficients. 
   
     
     
         19 . The code modulating method according to  claim 18 , wherein the input signal is one-bit data.