SAMPLED DATA FILTER

• US 3,621,402 A
• Filed: 08/03/1970
• Issued: 11/16/1971
• Est. Priority Date: 08/03/1970
• Status: Expired due to Term

• Current Assignee: N/A
• Original Assignee: N/A
• Primary Examiner(s): John S. Heyman
• Assistant Examiner(s): R. E. Hart
• Application Number:
  US05/060,558
• Time in Patent Office: 470 Days
• Field of Search: 307/221,238 328/37,151,51,122,167
• US Class Current: 377/57
• CPC Class Codes: H03H 15/02 using analogue shift registers

Abstract

A sampled data filter is disclosed comprising a plurality of amplifiers interconnected by delay units and feedback resistors. Each delay unit comprises the cascade connection of actuable switches and storage capacitors. The values of the capacitors and feedback resistors are preselected to obtain a desired transfer function and to nullify the effects of residual capacitor charge.

Claims

1. A sampled data filter comprising:

a first amplifier responsive to an applied input signal;

first delay means, responsive to the output signal of said first amplifier, comprising a plurality of actuable switches connecting a plurality of storage capacitors;

a second amplifier responsive to the output signal of said first delay means;

second delay means, responsive to the output signal of said second amplifier, comprising a plurality of actuable switches connecting a plurality of storage capacitors;

first feedback means connecting the input and output of said first amplifier;

second feedback means connecting the input and of said second amplifier;

third feedback means connecting the output of said first delay means to the input of said first amplifier;

fourth feedback means connecting the output of said second delay means to the input of said second amplifier;

fifth feedback means connecting the output of said second delay means to the input of said first amplifier; and

means for selectively actuating the respective switches of said first and second delay means.

2. The sampled data filter of claim 1 further comprising:

a third amplifier responsive to the output signals of said first amplifier and said first and second delay means; and

sixth feedback means connecting the input and output of said third amplifier.

3. The sampled data filter of claim 1 further comprising:

a third amplifier;

first circuit means for applying the output signal of said first amplifier to said third amplifier;

second circuit means for applying the output signal of said first delay means to said third amplifier;

third circuit means for applying the output signal of said second delay means to said third amplifier; and

sixth feedback means connecting the input and output of said third amplifier.

4. A sampled data filter comprising:

first amplifier means responsive to an applied input signal;

first delay means, responsive to the output signal of said first amplifier means, comprising a plurality of actuable switches connecting a plurality of storage capacitors;

first feedback means connecting the input and output of said first amplifier means;

second feedback means connecting the output of said first delay means to the input of said first amplifier means; and

control means for selectively actuating the respective switches of said delay means.

5. The sampled data filter of claim 4 further comprising:

second amplifier means responsive to the output of said first delay means;

second delay means, responsive to the output signal of said second amplifier means, comprising a plurality of actuable switches connecting a plurality of storage capacitors;

third feedback means connecting the input and output of said second amplifier means;

fourth feedback means connecting the output of said second delay means to the input of said second amplifier means;

fifth feedback means connecting the output of said second delay means to the input of said first amplifier means; and

means responsive to said control means for selectively actuating the respective switches of said second delay means.

6. The sampled data filter of claim 5 further comprising:

third amplifier means responsive to the output signals of said first amplifier means and said first and second delay means; and

sixth feedback means connecting the input and output of said third amplifier.

7. A sampled data filter comprising:

a first amplifier responsive to an applied input signal;

first delay means, responsive to the output signal of said first amplifier, comprising the serial connection of a first switch, a first capacitor, a second switch a second capacitor, and a third switch;

a second amplifier responsive to the output signal of said first delay means;

second delay means, responsive to the output signal of said second amplifier, comprising the serial connection of a first switch, a first capacitor, a second switch, a second capacitor and a third switch;

first resistor means connecting the input and output of said first amplifier;

second resistor means connecting the input and output of said second amplifier;

third resistor means connecting the output of said first delay means to the input of said first amplifier;

fourth resistor means connecting the output of said second delay means to the input of said second amplifier;

fifth resistor means connecting the output of said second delay means to the input of said first amplifier; and

means for selectively operating the respective switches of said first and second delay means.

8. The sampled data filter of claim 7 further comprising:

a third amplifier responsive to the output signals of said first amplifier and said first and second delay means; and

sixth resistor means connecting the input and output of said third amplifier.

9. The sampled data filter of claim 7 further comprising:

a third amplifier;

sixth resistor means for applying the output signal of said first amplifier to said third amplifier;

seventh resistor means for applying the output signal of said first delay means to said third amplifier;

eighth resistor means for applying the output signal of said second delay means to said third amplifier; and

ninth resistor means connecting the input and output of said third amplifier.