Automatic gain control for motion encoder signals
View Patent ↗Disclosed are various embodiments of pulse generation and automatic gain control (“AGC”) circuits and corresponding methods that are especially well suited for use in motion encoding systems. Analog output signals provided by a motion encoder serve as inputs to the pulse generation circuit, where peaks, valleys and/or crosspoints corresponding to such analog signals are first detected and then employed to generate output pulses corresponding thereto. These output pulses are next provided to an AGC circuit as self-generated clock signals which control the time windows over which the analog signals of the motion encoder are sampled and processed by the AGC circuit so as to adjust the gains applied to such analog signals.
1. A method of applying automatic gain control (“AGC”) to a plurality of analog output signals generated by a motion encoder, comprising:
generating, with the motion encoder, the plurality of analog output signals, such output signals being out of phase respecting one another, the plurality of analog output signals having peaks and valleys corresponding thereto;
providing the analog output signals to a pulse generation circuit;
generating, with the pulse generation circuit, digital pulses corresponding to the peaks and valleys of the analog output signals, and
employing, in an AGC circuit, the generated digital pulses as clock signals to control sampling of and adjust gains applied to at least one of the analog output signals.
2. The method of claim 1 , wherein the plurality of analog output signals comprise signals corresponding to Channel A, Channel A/, Channel B, and Channel B/ signals of the motion encoder.
3. The method of claim 2 , further comprising providing the Channel A and Channel A/ signals to the pulse generation circuit and generating digital pulses corresponding to predetermined ones of the peaks or valleys of the Channel B or Channel B/ signals.
4. The method of claim 2 , further comprising providing the Channel B and Channel B/ signals to the pulse generation circuit and generating digital pulses corresponding to predetermined ones of the peaks or valleys of the Channel A or Channel A/ signals.
5. The method of claim 2 , wherein crosspoints are associated with the Channel A, Channel A/, Channel B, and Channel B/ signals, and pulses corresponding to such crosspoints are generated by the pulse generation circuit and provided to the AGC circuit to aid in controlling sampling and adjusting gains applied to at least one of the Channel A, Channel A/, Channel B, and Channel B/ signals.
6. The method of claim 5 , further comprising providing the Channel B and Channel B/ signals to the pulse generation circuit and generating digital pulses corresponding to crosspoints of the Channel A or Channel B signals.
7. The method of claim 2 , further comprising providing to the AGC circuit at least one predetermined reference voltage V ref and comparing V ref to at least one voltage corresponding to the Channel A, Channel A/, Channel B, or Channel B/ signals.
8. The method of claim 7 , further comprising providing to the AGC circuit predetermined voltages V high and V low and comparing V high and V low to at least one voltage corresponding to the Channel A, Channel A/, Channel B, and Channel B/ signals.
9. The method of claim 8 , further comprising adjusting a gain of at least one of the Channel A, Channel A/, Channel B, or Channel B/ signals by generating a control signal on the basis of comparing V high and V low to the at least one voltage and providing the control signal to a variable resistor operably connected to a transimpedance amplifier, the transimpedance amplifier being configured to increase or decrease the gain applied to the Channel A, Channel A/, Channel B, or Channel B/ signal.
10. A motion encoding system configured to apply automatic gain control (“AGC”) to a plurality of analog output signals, comprising:
a motion encoder configured to generate the plurality of analog output signals, each of such signals being out of phase respecting the others, each of the analog output signals having peaks and valleys corresponding thereto;
a pulse generation circuit operably connected to the motion encoder and configured to receive the analog output signals therefrom, the pulse generation circuit being configured to generate digital pulses corresponding to the peaks and valleys of the analog output signals, and
an AGC circuit configured to receive the digital pulses and employ the digital pulses as clock signals to control sampling of and adjust gains applied to at least one of the analog output signals.
11. The system of claim 10 , wherein the plurality of analog output signals comprise signals corresponding to Channel A, Channel A/, Channel B, and Channel B/ signals of the motion encoder.
12. The system of claim 11 , wherein the pulse generation circuit is configured to receive the Channel A and Channel A/ signals and generate digital pulses corresponding to predetermined ones of the peaks or valleys of the Channel B or Channel B/ signals.
13. The system of claim 11 , wherein the pulse generation circuit is configured to receive the Channel B and Channel B/ signals and generate digital pulses corresponding to predetermined ones of the peaks or valleys of the Channel A or Channel A/ signals.
14. The system of claim 11 , wherein crosspoints are associated with the Channel A, Channel A/, Channel B, and Channel B/ signals, and the pulse generation circuit is configured to generate digital pulses corresponding to such crosspoints and provide such digital pulses to the AGC circuit to aid in controlling sampling and adjusting gains applied to at least one of the Channel A, Channel A/, Channel B, and Channel B/ signals.
15. The system of claim 14 , further comprising configuring the pulse generation circuit to receive the Channel B and Channel B/ signals and generate digital pulses corresponding to crosspoints of the Channel A or Channel B signals.
16. The system of claim 11 , further comprising configuring the AGC circuit to provide at least one predetermined reference voltage V ref and compare V ref to at least one voltage corresponding to the Channel A, Channel A/, Channel B, or Channel B/ signals.
17. The system of claim 16 , further comprising configuring the AGC circuit to provide predetermined voltages V high and V low and compare V high and V low to at least one voltage corresponding to the Channel A, Channel A/, Channel B, and Channel B/ signals.
18. The system of claim 17 , further comprising configuring the AGC circuit to adjust a gain of at least one of the Channel A, Channel A/, Channel B, or Channel B/ signals by generating a control signal on the basis of comparing V high and V low to the at least one voltage and providing the control signal to a variable resistor operably connected to a transimpedance amplifier, the transimpedance amplifier being configured to increase or decrease the gain applied to the Channel A, Channel A/, Channel B, or Channel B/ signal.
19. The system of claim 11 , wherein no separate or external oscillator or clock circuit is operably coupled to or included in the AGC circuit.
20. The system of claim 11 , wherein the pulse generation circuit and the AGC circuit are incorporated into a single integrated circuit, the integrated circuit further not comprising a separate or external oscillator or clock circuit operably coupled to or included in the AGC circuit.