Diversity radio receiver
First Claim
1. A diversity radio receiver for receiving and demodulating digital modulated signals with delayed and differential detection, said receiver comprising:
- a plurality of reception branch means for respectively receiving the digital modulated signals and converting received digital modulated signals into intermediate frequency signals having frequency differences having a predetermined correspondence to a modulation baseband signal;
adding means for adding the intermediate frequency signals converted by said plurality of reception branch means;
delayed and differential detection means for delaying and differentially detecting a sum signal from said adding means; and
post detection filter means for filtering a signal delayed and detected by said delayed and differential detection means, using a bandwidth of not less than a Nyquist frequency of the received digital modulated signals, thereby outputting demodulated signals of the received digital modulated signals,wherein said plurality of reception branch means set the frequency differences having the predetermined relationship so as to satisfy the following equations if the frequencies of the intermediate frequency signals are given as fi1 and fi2;
space="preserve" listing-type="equation">fi1=fi+m·
fB/d, and fi2=fi+n·
fB/dwherefi;
a nominal intermediate frequency of the received digital modulated signals,fB;
a baud rate of the modulation baseband signal,d;
a delay baud count of said delayed and differential detection means, andm, n;
integers satisfying m˜
n≧
d/2 (wherein ˜
represents a subtraction).
1 Assignment
0 Petitions
Accused Products
Abstract
A plurality of reception branches receive digital modulated signals and convert received digital modulated signals into intermediate frequency signals having frequency differences having a predetermined relationship with a modulation baseband signal. An adder adds the intermediate frequency signals converted by the plurality of reception branches. A delayed and differential detection section delays and differentially detects a sum signal from the adder. A post detection filter filters a delayed and differentially detected signal from the delayed and differential detection section at a bandwidth higher than a Nyquist frequency of the received digital modulated signals, thereby outputting demodulated signals of the received digital modulated signals.
120 Citations
13 Claims
-
1. A diversity radio receiver for receiving and demodulating digital modulated signals with delayed and differential detection, said receiver comprising:
-
a plurality of reception branch means for respectively receiving the digital modulated signals and converting received digital modulated signals into intermediate frequency signals having frequency differences having a predetermined correspondence to a modulation baseband signal; adding means for adding the intermediate frequency signals converted by said plurality of reception branch means; delayed and differential detection means for delaying and differentially detecting a sum signal from said adding means; and post detection filter means for filtering a signal delayed and detected by said delayed and differential detection means, using a bandwidth of not less than a Nyquist frequency of the received digital modulated signals, thereby outputting demodulated signals of the received digital modulated signals, wherein said plurality of reception branch means set the frequency differences having the predetermined relationship so as to satisfy the following equations if the frequencies of the intermediate frequency signals are given as fi1 and fi2;
space="preserve" listing-type="equation">fi1=fi+m·
fB/d, and fi2=fi+n·
fB/dwhere fi;
a nominal intermediate frequency of the received digital modulated signals,fB;
a baud rate of the modulation baseband signal,d;
a delay baud count of said delayed and differential detection means, andm, n;
integers satisfying m˜
n≧
d/2 (wherein ˜
represents a subtraction). - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A diversity radio receiver for receiving and demodulating digital modulated signals with delayed and differential detection, said receiver comprising:
-
a plurality of reception branch means for respectively receiving the digital modulated signals and converting received digital modulated signals into intermediate frequency signals having frequency differences having a predetermined correspondence to a modulation baseband signal; adding means for adding the intermediate frequency signals converted by said plurality of reception branch means; frequency converting means for mixing a sum signal from said adding means with a signal having a frequency equal to a nominal center frequency of the intermediate frequency signal, thereby converting the sum signal into a low-frequency band signal; baseband delayed and differential detection means for performing differential logic processing of the low-frequency band signal converted by said frequency converting means to perform baseband delayed and differential detection; and post detection filter means for filtering a signal detected by said baseband delayed and differential detection means, at a predetermined bandwidth, thereby outputting a demodulated signal of the received digital modulated signals, wherein said plurality of reception branch means set the frequency differences having the predetermined relationship so as to satisfy the following equations if the frequencies of the intermediate frequency signals are given as fi1 and fi2;
space="preserve" listing-type="equation">fi1=fi+m·
fB/d, and fi2=fi+n·
fB/dwhere fi;
a nominal intermediate frequency of the received digital modulated signals,fB;
a baud rate of the modulation baseband signal,d;
a delay baud count of said delayed and differential detection means, andm, n;
integers satisfying m˜
n≧
d/2 (wherein ˜
represents a subtraction),so that the frequency difference is set to be no less than a Nyquist frequency of the received digital modulated signal. - View Dependent Claims (8, 9, 10, 11, 12, 13)
-
Specification