Ring-down Box

Application of the ring-down box

You can measure the finesse of a resonator with the ring-down box without locking the resonator!

Advantages

super fast (see characterization)

without locking the resonator

Measurement Method

Evaluation

Use this formula to analyse the datapoints with : time, : delay time

Afterwards calculate the finesse with with : free spectral range.

Electronic setup

max. Input PD-voltage: +5V or -5V

Output TTL (Name: inv. Q): 5V

Power voltage: +/-15 or +/-18V (max.)

Switch A: unten = Eingang invertierend, oben = deaktiviert

Switch B: unten = Ringdown Messung, oben = dauer-reset

Explanation of the operating principle

Electronic drawing: Electronic drawing_Ring_down_Box

Characterization

List of components

Inverter: LT1363

Invert negative input voltage to positive

Datasheet_LT1363

Power supply: +/-5V

Comparator: AD8561

Compare input voltage and threshold value

Datasheet_AD8561

Power supply: +/-5V

High speed timing: 7ns @ 5V

Flip-Flop: SN74HC74

Output of trigger

Datasheet_SN74HC74

Power supply: +5V

High speed timing: 15ns

1x XLR connector

1x Power supply +/-5V

1x single switch

1x double switch

3x BNC connctors

1x Potentiometer

1x big red button

2x 8-pin IC socket

1x 14-pin IC socket

3x PSK 3-pin cables

5x 100n capacitors

some resistors (3x 100k, 1x 4.7k, …)

1x Al-box

2x PCBs

Microwave switch

Control of RF signal to the AOM

Mixer typ: SRA-1+ (Datasheet_SRA-1+)

1x Resistor (100 Ohm)

2x diodes (type: 1N4748)

1x diode (type: Z3,9V)

3x BNC connectors

1x Al-Box

Connect all ground pins to ground, also the housing