Ultrasonic sensor having enhanced dynamic range

In a detector for sensing energy in the ultrasonic frequency range:

• a transducer responsive to ultrasonic energy incident thereon for generating a first electrical signal that is related to the intensity and frequency of the ultrasonic energy;
• an oscillator having a selectable frequency of operation for generating a second electrical signal differing from the frequency of the first signal by an amount within an audio frequency range;
• a heterodyning stage responsive to the first and second signals for generating a third electrical signal having a frequency equal to a difference of the frequencies of the first and second signals;
• and
• an amplifier for amplifying the third signal, the amplifier including means for reducing the gain presented to higher frequency components of the third signal to concentrate the spectral energy of the third signal in a lower portion of the audio frequency range.

In a detector for sensing energy in the ultrasonic frequency range:

• a transducer responsive to ultrasonic energy incident thereon for generating a first electrical signal that is related to the intensity and frequency of the ultrasonic energy;
• an oscillator having a selectable frequency of operation for generating a second electrical signal differing from the frequency of the first signal by an amount within an audio frequency range;
• a first device for chopping the first signal with the output of the oscillator to generate a third electrical signal having a frequency equal to a difference of the frequencies of the first and second signals;
• an amplifier coupled to the output of the first device for concentrating the spectral energy of the third signal in a lower portion of the audio range;
• and
• a low pass filter coupled to the output of the first device for extracting a fourth signal exhibiting a lower portion of the spectrum of the so-concentrated third signal.

In a detector for sensing energy in the ultrasonic frequency range:

• a transducer responsive to ultrasonic energy incident thereon for generating a first electrical signal that is related to the intensity and frequency of the ultrasonic energy;
• an oscillator having a selectable frequency of operation for generating a second electrical signal differing from the frequency of the first signal by an amount within an audio frequency range;
• a heterodyning stage responsive to the first and second signals for generating a third electrical signal having a frequency equal to a difference of the frequencies of the first and second signals;
• an amplifier for amplifying the third signal, the amplifier including a device for reducing the gain presented to higher frequency components of the third signal to concentrate the spectral energy of the third signal in a lower portion of the audio frequency range;
• and
• a low pass filter coupled to the output of the amplifier for extracting a fourth signal exhibiting a lower portion of the spectrum of the concentrated third signal.

A detector for sensing energy in the ultrasonic frequency range and for providing an indication of the level of such energy at an external monitoring device, which comprises:

• a transducer responsive to ultrasonic energy incident thereon for generating a first electrical signal that is related to the intensity and frequency of the ultrasonic energy;
• an oscillator having a selectable frequency of operation for generating a second electrical signal differing from the frequency of the first signal by an amount within an audio frequency range;
• a heterodyning stage responsive to the first and second signals for generating a third electrical signal having a frequency equal to a difference of the frequencies of the first and second signals;
• a first amplifier coupled to the output of the heterodyning stage for concentrating the spectral energy of the third signal in a lower portion of the audio frequency range;
• a low pass filter coupled to the output of the first amplifier for extracting a fourth signal exhibiting a lower portion of the spectrum of the concentrated third signal;
• and
• a device for coupling the fourth signal to a monitoring device.

A detector for sensing energy in the ultrasonic frequency range and for providing an indication of the level of such energy at an external monitoring device, which comprises:

• a transducer responsive to ultrasonic energy incident thereon for generating a first electrical signal that is related to the intensity and frequency of the ultrasonic energy;
• an oscillator for generating a second electrical signal having a selectable frequency differing from the frequency of the first signal by an amount within the audio frequency range;
• first means responsive to the first and second signals for generating a third electrical signal having a frequency equal to the difference of the frequencies of the first and second signals;
• means including a first amplifier coupled to the output of the first generating means for concentrating the spectral energy of the third signal in a lower portion of the audio range;
• a low pass filter coupled to the output of the amplifying means for extracting a fourth signal exhibiting a lower portion of the spectrum of the concentrated third signal;
• second means having a first input coupled to the low pass filter for generating a first DC quantity having a level related to the amplitude of the fourth signal;
• and
• means for coupling the first DC quantity to the monitoring device.

A detector for sensing energy in the ultrasonic frequency range and for providing an indication of the level of such energy to first and second external measuring devices, which comprises:

• a transducer responsive to ultrasonic energy incident thereon for generating a first electrical signal that is related to the intensity and frequency of the ultrasonic energy;
• an oscillator for generating a second electrical signal having a selectable frequency differing from the frequency of the first signal by an amount within the audio frequency range;
• first means responsive to the first and second signals for generating a third electrical signal having a frequency equal to the difference of the frequencies of the first and second signals;
• means including a first amplifier coupled to the output of the first generating means for concentrating the spectral energy of the third signal in a lower portion of the audio range;
• a low pass filter coupled to the output of the amplifying means for extracting a fourth signal exhibiting a lower portion of the spectrum of the concentrated third signal;
• means for coupling the fourth signal to the first measuring device;
• second means having a first input coupled to the low pass filter for generating a DC quantity having a level related to the amplitude of the fourth signal;
• and
• means for coupling the DC quantity to the second measuring device.