The present invention provides an apparatus of transmitting broadcast signals. The apparatus includes, an encoder encoding service data, a constellation mapper mapping the encoded service data by either QAM, NUQ (Non Uniform QAM) or NUC (Non Uniform Constellation), a mapper mapping the mapped service data into a plurality of OFDM (Orthogonal Frequency Division Multiplex) symbols to build at least one signal frame, a modulator modulating data in the built at least one signal frame by an OFDM scheme and a transmitter transmitting the broadcast signals having the modulated data.

A system and method are provided relating generally to data transmission and more particularly to modulation techniques offering increased data transmission rates. To so provide, a first amplitude-time modulated (ATM) signal and a first phase modulated signal are combined at a first combiner to produce a complex wave modulation signal, and the complex wave modulation signal and an additional signal are combined at a second combiner to produce a second complex wave modulation signal. The additional signal may be a second ATM signal or a second phase modulated signal. Optionally, the second complex wave modulation signal and a second additional signal may be combined to produce a third complex wave modulation signal. In accordance with at least one embodiment, a shape of an element of information according to the first ATM signal may be defined programmatically over subportions of less than the duration of the element of information.

An optical transceiver comprising an optical signal input, a first modulation section coupled to the optical signal input, a second modulation section coupled to the optical signal input and positioned in serial with the first modulation section, wherein the first modulation section comprises a first digital electrical signal input, a first digital driver coupled to the first digital electrical signal input, and a first modulator coupled to the first digital driver, and wherein the second modulation section comprises a second digital electrical signal input, a second digital driver coupled to the second digital electrical signal input, and a second modulator coupled to the second digital driver, and an optical signal output coupled to the first modulation section and the second modulation section.

Examples described herein include backscatter devices which may transmit orthogonal frequency division multiplexing (OFDM) signals. Techniques for complex analog backscatter are described. Examples of impedance circuitry are described which may be used to provide real and imaginary components of impedance in accordance with inphase and quadrature bits.

According to some embodiments, an apparatus for generating multiple variable frequency and phase locked clock signals comprises complex tuners, digital up-samplers, image isolation filters, quadrature modulators, a combiner, a DAC, a local oscillator, and an analog filter. The complex tuners tune multiple digital baseband signals. The up-samplers interpolate the complex tuned digital signals such that one of the up-sampled images of each of the complex tuned digital signals corresponds to a desired frequency. The image isolation filters isolate images corresponding to the desired frequencies. The quadrature modulators convert the isolated images of the complex tuned digital signals into real digital signals. The combiner combines the real digital signals into a combined real digital signal. The DAC, driven by the local oscillator, converts the combined real digital signal into an analog clock signal. The analog filter then filters the analog clock signal to select images located at the desired frequencies.

Disclosed are a real number M-ary signal encoding method, where M is a real number having N time dimensions and L frequency dimensions, and an encoding apparatus using the encoding method. The real number M-ary encoding apparatus according to the present invention comprises a coding unit which codes every K (K is an integer) binary bit units of binary data DATA to generate a first input code and a second input code, a first signal generator which receives the first input code and generates N.sub.1 number of M.sub.1-ary signals, a second signal generator which receives the second input code and generates N.sub.2 number of M.sub.2-ary signals, and a first time division multiplexing module which temporally multiplexes the N.sub.1 number of M.sub.1-ary signals and the N.sub.2 number of M.sub.2-ary signals to generate a real number M-ary signal which utilizes a voltage ratio a (a=A.sub.2/A.sub.1) used for M.sub.1-ary and M.sub.2-ary signals to minimize a transmission error rate.

The present invention provides an apparatus of transmitting broadcast signals. The apparatus includes, an encoder encoding service data, a constellation mapper mapping the encoded service data by either QAM, NUQ (Non Uniform QAM) or NUC (Non Uniform Constellation), a mapper mapping the mapped service data into a plurality of OFDM (Orthogonal Frequency Division Multiplex) symbols to build at least one signal frame, a modulator modulating data in the built at least one signal frame by an OFDM scheme and a transmitter transmitting the broadcast signals having the modulated data.

An FBMC signal transmitting method and receiving method, a transmitter, and a receiver are provided. The transmitting method includes: generating offset quadrature amplitude modulation OQAM symbols included on at least two subbands; mapping an OQAM symbol on each subband onto a respective subcarrier to obtain a frequency-domain signal, where a first frequency interval exists between adjacent subcarriers in a same subband, a second frequency interval exists between adjacent subcarriers that belong to two adjacent subbands, the second frequency interval is a sum of the first frequency interval and a guard band interval, and the guard band interval is a fractional multiple of the first frequency interval; generating an FBMC signal out of the frequency-domain signal; and transmitting the FBMC signal to a receiver.

A method for channel aggregation and single sideband transmission executed in a broad-band communication system is suggested in which only I and Q versions of a purely sinusoidal local oscillator signals are needed, easing the system scaling when large numbers of channels must be aggregated. In addition to that, instead of phase shifting of an intermediate frequency broadband signal rather two intermediate frequency broadband signals are generated, which are phase shifted by +90? or by ?90?. As a result, the problems of frequency dependent phase shifting explained in the background section is not relevant for the method according to the present disclosure. Also, a corresponding method for image reject reception and channel separation as well as a transmitter and receiver for performing the methods are suggested.

A method for determining a noise shaped quantized parameter contributing to generation of an output signal comprises estimating an error within the output signal using a quantization of the parameter and a quantization of a further parameter contributing to generation of the output signal. The quantization of the parameter is used as the noise shaped quantized parameter according to a selection criterion.