Barcode scanner with linear automatic gain control (AGC), modulation transfer function detector, and selectable noise filter

A method, comprising:

• receiving at a first gain element and a second gain element a gain signal, the gain signal based on a predetermined amplitude for an analog signal representative of a barcode, the first gain element matched to the second gain element;
• generating a linear response to the gain signal using the first and the second gain elements;
• applying the analog signal to a positive input of an operational amplifier;
• and
• applying the linear response to the gain signal to a negative input of the operational amplifier.

A method, comprising:

• receiving at a gain element a gain signal, the gain signal based on a predetermined amplitude for an analog signal representative of a barcode, the gain element having a response;
• generating a linear response to the gain signal using a map of the gain element response;
• applying the analog signal to a positive input of an operational amplifier;
• and
• applying the linear response to the gain signal to a negative input of the operational amplifier.

An apparatus, comprising:

• a gain element to receive a gain signal, the gain signal based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode, the gain element having a response;
• and
• a map of the gain element response, the combination of the gain element response and the map of the gain element response to generate a linear response to the gain signal;
• and
• circuitry to apply the linear response to the first analog signal to generate a second analog signal.

A method, comprising:

• determining that an amplitude of a first frequency portion of an analog signal representing a barcode is approximately equal to an amplitude of a second frequency portion of the analog signal;
• determining that a noise filter is OFF;
• determining that a read rate is less than a predetermined value;
• and
• turning the noise filter ON in response to the read rate being less than the predetermined value.

An apparatus, comprising:

• a first gain element and a second gain element matched to the first gain element to generate a linear response to a gain signal, the gain signal being based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode;
• circuitry to apply the linear response to the first analog signal to generate a second analog signal;
• circuitry to determine an amplitude of a first frequency portion of the second analog signal, and to determine an amplitude of a second frequency portion of the second analog signal;
• and
• logic to determine that the amplitude of the first frequency portion is approximately equal to the amplitude of the second frequency portion to determine that a noise filter is OFF, to determine that a read rate is less than a predetermined value, and to turn the noise filter ON in response to the read rate being less than the predetermined value.

An apparatus, comprising:

• a gain element having a response;
• a map of the gain element response, the combination of the gain element and the map of the gain element response to generate a linear response to a gain signal, the gain signal based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode;
• circuitry to apply the linear response to the first analog signal to generate a second analog signal;
• logic to determine an amplitude of a first frequency portion of the second analog signal, and to determine an amplitude of a second frequency portion of the second analog signal;
• and
• logic to determine that the amplitude of the first frequency portion is approximately equal to the amplitude of the second frequency portion to determine that a noise filter is OFF, to determine that a read rate is less than a predetermined value, and to turn the noise filter ON in response to the read rate being less than the predetermined value.

An apparatus, comprising:

• a first gain element and a second gain element matched to the first gain element to generate a linear response to a gain signal, the gain signal being based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode;
• circuitry to apply the linear response to the first analog signal to generate a second analog signal;
• and
• logic to determine an amplitude of a first frequency portion of at least a portion of the second analog signal, and to determine an amplitude of a second frequency portion of at least a portion of the second analog signal.

An apparatus, comprising:

• a first gain element and a second gain element matched to the first gain element to generate a linear response to a gain signal, the gain signal being based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode;
• circuitry to apply the linear response to the first analog signal to generate a second analog signal;
• and
• logic to determine an amplitude of a first frequency portion of the second analog signal is approximately equal to an amplitude of a second frequency portion of the second analog signal, to determine that a noise filter is OFF, to determine that a read rate is less than a predetermined value, and to turn the noise filter ON in response to the read rate being less than the predetermined value.

An apparatus, comprising:

• a gain element having a response;
• a map of the gain element response, the combination of the gain element and the map of the gain element response to generate a linear response to a gain signal, the gain signal based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode;
• circuitry to apply the linear response to the first analog signal to generate a second analog signal;
• and
• logic to determine an amplitude of a first frequency portion of at least a portion of the second analog signal, and to determine an amplitude of a second frequency portion of at least a portion of the second analog signal.

An apparatus, comprising:

• a gain element having a response;
• a map of the gain element response, the combination of the gain element and the map of the gain element response to generate a linear response to a gain signal, the gain signal based on a predetermined amplitude for a first analog signal, the first analog signal being representative of a barcode;
• circuitry to apply the linear response to the first analog signal to generate a second analog signal;
• and
• logic to determine an amplitude of a first frequency portion of the second analog signal is approximately equal to an amplitude of a second frequency portion of the second analog signal, to determine that a noise filter is OFF, to determine that a read rate is less than a predetermined value, and to turn the noise filter ON in response to the read rate being less than the predetermined value.