Amplification circuit

• US 3,893,035 A
• Filed: 10/26/1973
• Issued: 07/01/1975
• Est. Priority Date: 11/04/1972
• Status: Expired due to Term

• Current Assignee: Kenneth Henry Higgens
• Original Assignee: Kenneth Henry Higgens
• Inventors: Higgens, Kenneth Henry
• Primary Examiner(s): Zazworsky, John
• Application Number:
  US05/409,931
• Time in Patent Office: 613 Days
• Field of Search: 328/1,146 307/235R,308 340/52F,58
• US Class Current: 327/50
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0425 Means comprising permanent magnets, e.g. Hall-effect or Reed-switches
• CPC Class Codes: H03K 3/0231 Astable circuits H03K3/0315 takes precedence
• CPC Class Codes: H03K 5/02 by amplifying H03K5/04 takes precedence

Abstract

Amplification circuit, particularly suitable for use with a tire pressure reduction indication system, providing a pulsed output signal of predetermined frequency on receipt of a pulse input signal and a constant output signal for a change in D.C. voltage value of the input. The circuit may also include rejection means for rejecting input pulses below a certain amplitude, for rejecting changes in D.C. voltage level below a predetermined level or input pulses not having immediately preceding and following smaller pulses of opposite polarity.

Claims

1. Apparatus for detecting pulse signals from pulse generating means, comprising:

differential amplifying circuit means for generating an output signal having one of two possible voltage levels depending upon the voltage difference of input signals applied to said amplifying means, said amplifying means having first and second input terminals coupled to each other through a voltage dividing circuit to create a constant potential difference between said input terminals; and

a filter circuit coupled to one of said input terminals to substantially inhibit pulse signals from being applied to said one input terminal;

said amplifying means output signal changing its voltage level when a pulse signal appears at the other of said input terminals, the negative peak of said pulse signal exceeding the constant potential difference between said first and second input terminals.

2. The apparatus according to claim 1, further comprising:

means for detecting a change in level outside a preset range of the voltage applied to said first and second input terminals to create said constant potential difference, including first and second oppositely biased diodes coupled through respective voltage dividing circuits to said first and second input terminals of said differential amplifying circuit means, respectively.

3. The apparatus according to claim 1, further comprising circuit means for controlling the duration of the change in voltage level at the output of said differential amplifying circuit means, including capacitive and resistive impedance means coupled in series with each other between the output of said differential amplifying circuit means and said one input terminal of said amplifying means.

4. The apparatus according to claim 1, further comprising means for passing to said differential amplifying circuit means only those pulse signals having immediately preceding and following pulses of opposite polarity to and smaller amplitude than the main pulse signal, including a preamplifier circuit having its input coupled to said pulse signal generating means and a discriminator circuit having its input coupled to an output of said preamplifier circuit and its output coupled to said differential amplifying circuit means.