SEMICONDUCTOR APPARATUS AND RADIO CIRCUIT APPARATUS USING THE SAME

• US 20090115466A1
• Filed: 06/27/2006
• Published: 05/07/2009
• Est. Priority Date: 07/04/2005
• Status: Active Grant

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Maeda, Masakatsu
• Granted Patent: US 7,974,333 B2
• Time in Patent Office: Days
• US Class Current: 327/117
• CPC Class Codes: H03L 7/183 a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number H03L7/1806 takes precedence
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

A semiconductor apparatus includes a signal source 7 that outputs a signal of predetermined frequency, a frequency divider 15 that receives the output signal of the signal source and is capable of switching the output signal to two or more frequency division ratios, a delta-sigma modulator 16 that controls the frequency division ratio of the frequency divider, and a bandpass filter 17 that receives an output of the frequency divider. The frequency of the input signal of the frequency divider is divided by the frequency division ratio controlled by the delta-sigma modulator, and quantization noise appearing in the output of the frequency divider generated by the delta-sigma modulator is attenuated with the bandpass filter. The semiconductor apparatus easily can convert a signal output by a single signal source to a signal of predetermined frequency and supply a plurality of signals of predetermined frequency using a simple configuration with reduced chip size.

Claims

1. A semiconductor apparatus comprising:

a signal source that outputs a signal of predetermined frequency;

a frequency divider that receives the output signal of the signal source, and is capable of switching the output signal to two or more frequency division ratios;

a delta-sigma modulator that controls the frequency division ratio of the frequency divider; and

a bandpass filter that receives an output of the frequency divider, wherein

a frequency of the input signal of the frequency divider is divided by the frequency division ratio controlled by the delta-sigma modulator, and quantization noise appearing in the output of the frequency divider generated by the delta-sigma modulator is attenuated with the bandpass filter.

2. The semiconductor apparatus according to claim 1, further comprising a frequency characteristic adjusting unit that adjusts a frequency characteristic of the bandpass filter, wherein

the frequency characteristic adjusting unit adjusts the frequency characteristic of the bandpass filter to be in a predetermined state relative to the signal input from the frequency divider.

3. The semiconductor apparatus according to claim 1, wherein an LC resonator is used in the bandpass filter.

4. The semiconductor apparatus according to claim 3, wherein a voltage-controlled variable capacitor is used in the LC resonator.

5. The semiconductor apparatus according to claim 2, wherein the frequency characteristic adjusting unit adjusts the frequency characteristic of the bandpass filter based on an amplitude of the output signal of the bandpass filter.

6. The semiconductor apparatus according to claim 2, wherein the frequency characteristic adjusting unit adjusts the frequency characteristic of the bandpass filter based on a frequency of the output signal of the bandpass filter.

7. The semiconductor apparatus according to claim 2, wherein the frequency characteristic adjusting unit operates if an amplitude of the output signal of the bandpass filter is at or below a set value or if a frequency of the output signal of the bandpass filter deviates from a set frequency, other than when an adjustment instruction is input.

8. The semiconductor apparatus according to claim 1, further comprising a frequency detector that detects a frequency of the signal input to the frequency divider, wherein

the frequency division ratio of the frequency divider is adjusted according to the detection output.

9. The semiconductor apparatus according to claim 2, further comprising a fixed frequency divider between the frequency divider and the bandpass filter, wherein

quantization noise appearing in the output of the fixed frequency divider generated by the delta-sigma modulator is attenuated with the bandpass filter.

10. A radio circuit apparatus comprising:

a signal source that outputs a signal of predetermined frequency;

a frequency divider that receives the output signal of the signal source, and is capable of switching the output signal to two or more frequency division ratios;

a delta-sigma modulator that controls the frequency division ratio of the frequency divider; and

a bandpass filter that receives an output of the frequency divider, wherein

a frequency of the input signal of the frequency divider is divided by the frequency division ratio controlled by the delta-sigma modulator, and quantization noise appearing in the output of the frequency divider generated by the delta-sigma modulator is attenuated with the bandpass filter, and

an output signal of the bandpass filter is used as a carrier wave.

11. The radio circuit apparatus according to claim 10, further comprising a frequency characteristic adjusting unit that adjusts a frequency characteristic of the bandpass filter, wherein

the frequency characteristic adjusting unit adjusts the frequency characteristic of the bandpass filter to be in a predetermined state relative to the signal input from the frequency divider.

12. The radio circuit apparatus according to claim 10, wherein a modulation component is added to the frequency division ratio of the frequency divider controlled by the delta-sigma modulator.

13. The radio circuit apparatus according to any one of claims 10, comprising a plurality of frequency converting units each including the frequency divider, the bandpass filter and the delta-sigma modulator, wherein

the output signal of the single signal source is supplied to each of the plurality of frequency converting units.

14. The radio circuit apparatus according to claim 10, further comprising a fixed frequency divider between the frequency divider and the bandpass filter, wherein quantization noise appearing in the output of the fixed frequency divider generated by the delta-sigma modulator is attenuated with the bandpass filter.