diff options
Diffstat (limited to 'host/include')
| -rw-r--r-- | host/include/uhd/types/time_spec.hpp | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/host/include/uhd/types/time_spec.hpp b/host/include/uhd/types/time_spec.hpp index f06d27118..25d9e41d0 100644 --- a/host/include/uhd/types/time_spec.hpp +++ b/host/include/uhd/types/time_spec.hpp @@ -28,10 +28,19 @@ namespace uhd{ * The time_spec_t can be used when setting the time on devices, * and for dealing with time stamped samples though the metadata. * and for controlling the start of streaming for applicable dsps. + * + * The fractional seconds are represented in units of nanoseconds, + * which provide a clock-domain independent unit of time storage. + * The methods "get_ticks" and "set_ticks" can be used to convert + * the fractional seconds to and from clock-domain specific units. + * + * The nanoseconds count is stored as double precision floating point. + * This gives the fractional seconds enough precision to unambiguously + * specify a clock-tick/sample-count up to rates of several petahertz. */ struct UHD_API time_spec_t{ - //! whole seconds count + //! whole/integer seconds count in seconds boost::uint32_t secs; //! fractional seconds count in nano-seconds @@ -39,24 +48,26 @@ namespace uhd{ /*! * Convert the fractional nsecs to clock ticks. + * Translation into clock-domain specific units. * \param tick_rate the number of ticks per second - * \return the number of ticks in this time spec + * \return the fractional seconds tick count */ boost::uint32_t get_ticks(double tick_rate) const; /*! * Set the fractional nsecs from clock ticks. + * Translation from clock-domain specific units. * \param ticks the fractional seconds tick count * \param tick_rate the number of ticks per second */ void set_ticks(boost::uint32_t ticks, double tick_rate); /*! - * Create a time_spec_t from seconds and ticks. - * \param new_secs the new seconds (default = 0) - * \param new_nsecs the new nano-seconds (default = 0) + * Create a time_spec_t from whole and fractional seconds. + * \param secs the whole/integer seconds count in seconds (default = 0) + * \param nsecs the fractional seconds count in nanoseconds (default = 0) */ - time_spec_t(boost::uint32_t new_secs = 0, double new_nsecs = 0); + time_spec_t(boost::uint32_t secs = 0, double nsecs = 0); }; |