Oakley OMS-820, MOTM-820 instruction

again, as it crosses zero volts, the op-amp swings and the switcher responds... and the process repeats again and again and again.

Of course, the speed at which the process repeats is set by the UP and DOWN pots. You can get very fast at around 1000 complete cycles a second, and you can get very slow. Very slow indeed.

On my MOTM-820 I noticed slight instability in the waveform when driven very fast in LOG mode. This is feature of the MOTM’s circuit core, and not a fault of the OMS unit.

The envelope generator (EG) is more complex, but the principle is very similar to the LFO really. However, an EG will not cycle endlessly, but needs trigger signals to initiate certain phases. The OMS-820 in conjunction with the MOTM-820 form a very powerful envelope generator, that behaves quite different from your usual ADSR type. It has four modes, of which the attack-decay (AD) mode is the most complex.

The GATE input is applied to initiate the attack phase. This is a switch type signal that is either at around 0 volts when off, or any positive voltage greater than 3V when on. The OMS- 820 can easily handle greater voltages without damage. D8 protects Q9 from any negative inputs.

A push switch, G-S, named GATE on the front panel, can also be pressed to initiate the attack phase. C4 and R19 smooth off any contact bouncing in the switch. D6 prevents C4 from smoothing any incoming gate signal, which would not be a good thing leading to unwanted delays.

When a positive gate arrives, Q9 turns on and pulls its collector down to ground or 0V. This inverse version of the applied gate signal is sent to two destinations. One is another transistor, Q12. This is configured as another inverter. Thus the output of Q12 produces a copy of the gate signal that swings from 0 when off to +15V when on. R35 passes some current back to the first transistor. This creates a type of Schmitt trigger action which makes the transistors change state faster. It also allows slowly varying signals to trigger the OMS-820. For example you can use a slow sine wave or aftertouch CV to fire the EG.

The output of Q12 is passed on to a CR network that acts as a differentiator. This circuit produces a positive voltage spike when the gate goes high. The duration of the spike is determined principally by the values of C6 and R23. D5 prevents a negative spike being produced when the gate goes low. The positive spike triggers an RS flip-flop circuit based around two NOR gates, U4.

A flip-flop is a sort of a one bit memory, or latch. Once triggered by a positive going pulse at pin 1, it stays latched. You can only reset it by removing the power or a reset pulse at its other input, pin 9. When the flip-flop is latched, pin 10 goes high and pin 4 goes low. The output at pin 10 is passed via R16 to the MOTM-820’s input, thus causing the MOTM to start to charge upwards. R16 is chosen to interact with the MOTM’s input impedance of 100K to give an input signal of 7.5V in the high state. When the flip-flop is active the SET LED is lit. Several sources are able to reset the flip-flop, which one depends on the mode you have selected.

MOTM-820, OMS-820 specifications

The Oakley OMS-820 and MOTM-820 stand out as exemplary models in Oakley's extensive range of performance eyewear, designed for both sports enthusiasts and everyday users. These models capture the essence of Oakley's commitment to innovation, superior optical technology, and stylish design.

One of the main features of the OMS-820 is its advanced lens technology. Utilizing Oakley’s High Definition Optics (HDO), the lenses provide exceptional clarity and optical fidelity. This technology minimizes distortion, ensuring that users have an unobstructed view, whether they are on the golf course, cycling, or participating in other outdoor activities. The lenses also come with Oakley's PRIZM technology, which enhances color contrast and visibility in various environments, allowing users to detect changes in terrain or obstacles more readily.

The MOTM-820, on the other hand, emphasizes adaptability and comfort. It features a lightweight frame crafted from Oakley’s proprietary O Matter material, which provides flexibility and resilience. This ergonomic design conforms to the shape of the wearer's face, ensuring a secure yet comfortable fit during extended use. The adjustable nose pads and temples further enhance comfort, making it ideal for an active lifestyle.

Both models incorporate Oakley’s innovative lens treatment technology, which includes anti-fog and anti-scratch advancements. This ensures that the eyewear remains clear in challenging conditions, whether users are facing misty weather or rugged terrains. Additionally, the UV protection offered by these lenses shields wearers from harmful rays, a critical feature for outdoor activities.

A striking characteristic of the Oakley OMS-820 and MOTM-820 is their customizable aesthetics. Available in a myriad of colors and styles, users can express their individuality while enjoying high-performance eyewear. This attention to style combined with functionality makes these models popular choices among both athletes and casual wearers alike.

In summary, the Oakley OMS-820 and MOTM-820 are distinguished models that integrate cutting-edge technology with comfort and style. Whether for competitive sports or daily wear, these eyewear options exemplify Oakley’s commitment to enhancing visual performance and user satisfaction.