Direct Digital Radio Frequency Modulator

Patent metadata

Field	Value
Publication number	US-2016234048-A1
Application number	US-201514857589-A
Country	US
Kind code	A1
Filing date	Sep 17, 2015
Priority date	Sep 19, 2014
Publication date	Aug 11, 2016
Grant date	—

Abstract

The present disclosure relates to a direct digital radio frequency modulator that includes a plurality of input terminals arranged to receive a multi-bit digital signal, and a plurality of converter circuits. In one example, the converter circuits are arranged to receive at an input terminal one bit of the multi-bit digital signal and to provide at a converter circuit output terminal an analog signal in accordance to the one bit. In the present example, a converter circuit includes an input transistor arranged to receive the one bit for enabling the converter circuit to produce the analog signal, a current source transistor, an additional transistor in cascode to the current source transistor, and a frequency modulator output terminal connected to the output terminal of each converter circuit for providing an analog output signal.

First claim

What is claimed is:

1 . A direct digital radio frequency modulator comprising:
a plurality of input terminals arranged to receive a multi-bit digital signal; and a plurality of converter circuits, wherein each converter circuit is arranged to receive at an input terminal one bit of the multi-bit digital signal and to provide at a converter circuit output terminal an analog signal in accordance to the one bit, wherein each converter circuit includes:
an input transistor arranged to receive the one bit for enabling the converter circuit to produce the analog signal,
a current source transistor,
an additional transistor in cascode to the current source transistor, and
a frequency modulator output terminal connected to the output terminal of each converter circuit for providing an analog output signal.

2 . The direct digital radio frequency modulator as in claim 1 , further comprising a circuit arranged for summing the analog signal produced by each respective converter circuit to form the analog output signal at the frequency modulator output terminal.

3 . The direct digital radio frequency modulator as in claim 1 , wherein the multi-bit digital signal is a modulated radio frequency multi-bit digital signal.

4 . The direct digital radio frequency modulator as in claim 3 , wherein the modulated radio frequency multi-bit digital signal is a modulated I/Q data signal or a modulated polar data signal.

5 . The direct digital radio frequency modulator as in claim 1 , wherein the current source transistor in each respective converter circuit is configured to receive a bias voltage.

6 . The direct digital radio frequency modulator as in claim 1 , wherein the additional transistor is a thick-oxide transistor.

7 . A front-end radio system comprising the direct digital radio frequency modulator as in claim 1 , and a digital signal processor arranged to provide the multi-bit digital signal.

8 . The front-end radio system as in claim 7 , wherein the digital signal processor comprises modulator circuitry arranged for modulating a digital baseband signal with a radio frequency signal and for outputting the multi-bit digital signal.

9 . A radio device comprising the front-end radio system as in claim 7 .

10 . A communication network comprising at least one radio device as in claim 9 .

Assignees

• Imec Vzw

Inventors

• Ingels Mark

Classifications

• H04L27/122 Primary

  using digital generation of carrier signals (digital function generators G06F1/02, H04L17/10; generating pulses having stepped portions using digital techniques H03K4/026) · CPC title

• H03C3/02

  Details · CPC title

• H03K5/01 Primary

  Shaping pulses (discrimination against noise or interference H03K5/125) · CPC title

• H04B1/0007

  wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage · CPC title