Semiconductor device and method therein

Patent metadata

Field	Value
Publication number	US-10211845-B2
Application number	US-201815967026-A
Country	US
Kind code	B2
Filing date	Apr 30, 2018
Priority date	Jun 20, 2017
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

Degradation of a reception performance by an image signal is reduced. A semiconductor device includes: an oscillation circuit configured to generate a local signal; a mixer configured to multiply a reception signal by the local signal; an analog filter configured to filter a signal output from the mixer; an AD converter configured to digitalize a signal that has passed through the analog filter to generate a first signal; a digital filter configured to filter a signal that has passed through the AD converter to generate a second signal; a power comparator configured to detect the power difference between the first signal and the second signal; a register configured to store a theoretical power difference; and a determination unit configured to determine a frequency of the local signal based on the power difference from the theoretical power difference.

First claim

What is claimed is:

1. A semiconductor device comprising:
an oscillation circuit configured to generate a local signal;
a mixer configured to multiply a reception signal by the local signal;
an analog filter configured to filter a signal output from the mixer;
an AD converter configured to digitalize a signal that has passed through the analog filter to generate a first signal;
a digital filter configured to filter a signal that has passed through the AD converter to generate a second signal;
a power comparator configured to detect the power difference between the power value of the first signal and the power value of the second signal;
a register configured to store a theoretical power difference, which is a power difference between the power value of the first signal and the power value of the second signal when there is no interfering wave; and
a determination unit configured to determine a frequency of the local signal based on the power difference detected by the power comparator and the theoretical power difference.

2. The semiconductor device according to claim 1 , wherein the determination unit determines the frequency of the local signal from among n types of (n is a natural number) candidate frequencies based on the power difference and the theoretical power difference.

3. The semiconductor device according to claim 2 , wherein
the determination unit controls the oscillation circuit in such a way that the oscillation circuit generates local signals of the n types of candidate frequencies,
the power comparator detects, for each of the n types of candidate frequencies, n power differences by detecting the power difference between the power value of the first signal and the power value of the second signal; and
the determination unit selects the power difference that is the closest to the theoretical power difference from among the n power differences and determines the candidate frequency that corresponds to the closest power difference as the frequency of the local signal.

4. The semiconductor device according to claim 1 , wherein
the determination unit controls the oscillation circuit in such a way that the oscillation circuit generates local signals of n types of (n is a natural number) candidate frequencies,
the power comparator detects, for each of the n types of candidate frequencies, n power differences by detecting the power difference between the power value of the first signal and the power value of the second signal; and
the determination unit obtains the order of the n power differences closer to the theoretical power difference and determines a further candidate frequency of the local signal based on the order of the closeness.

5. The semiconductor device according to claim 4 , wherein
the power comparator further detects, for the further candidate frequency, the power difference between the power value of the first signal and the power value of the second signal, and
the determination unit selects the power difference that is the closest to the theoretical power difference from among the n power differences and the power difference of the further candidate frequency and determines the candidate frequency that corresponds to the closest power difference as the frequency of the local signal.

6. A method comprising:
detecting a power difference between a power value of a first signal that is obtained by digitalizing a signal that has passed through an analog filter provided in the subsequent stage of a mixer and a power value of a second signal generated by the first signal passing through a digital filter; and
reading a theoretical power difference, which is a power difference between the power value of the first signal and the power value of the second signal when there is no interfering wave; and
determining a frequency of a local signal to be input to the mixer based on the power difference that has been detected and the theoretical power difference.

7. The method according to claim 6 , comprising determining the frequency of the local signal from among n types of (n is a natural number) candidate frequencies based on the power difference and the theoretical power difference.

8. The method according to claim 7 , comprising:
sequentially inputting local signals of the n types of candidate frequencies to the mixer;
detecting, for each of the n types of candidate frequencies, n power differences by detecting the power difference between the power value of the first signal and the power value of the second signal;
selecting the power difference that is the closest to the theoretical power difference from among the n power differences; and
determining the candidate frequency that corresponds to the closest power difference to be the frequency of the local signal.

9. The method according to claim 6 , comprising:
sequentially inputting local signals of n types of (n is a natural number) candidate frequencies to the mixer;
detecting, for each of the n types of candidate frequencies, n power differences by detecting the power difference between the power value of the first signal and the power value of the second signal;
obtaining the order of the n power differences closer to the theoretical power difference; and
determining a further candidate frequency of the local signal based on the order of the closeness.

10. The method according to claim 9 , comprising:
further detecting, for the further candidate frequency, the power difference between the power value of the first signal and the power value of the second signal;
selecting the power difference that is the closest to the theoretical power difference from among the n power differences and the power difference of the further candidate frequency; and
determining the candidate frequency that corresponds to the closest power difference to be the frequency of the local signal.

Assignees

• Renesas Electronics Corp

Inventors

• Naito Wataru
• Kondo Takeshi

Classifications

• H03M1/1023 Primary

  Offset correction (H03M1/1019 takes precedence; removal of offset already present on the analogue input signal H03M1/1295) · CPC title

• H04L2027/0067

  Phase error detectors · CPC title

• H03M2201/4212

  Electricity · mapped topic

• H04L2027/0065

  Frequency error detectors (H04L2027/0067 takes precedence) · CPC title

• H04B1/30 Primary

  for homodyne or synchrodyne receivers (demodulator circuits H03D1/22) · CPC title